CN107825014A - The backside gas protecting tool set-up and guard method that a kind of tube-to-tube sheet connection mutually welds - Google Patents

Abstract

The invention discloses a gas protection tool and a protection method on the back of a weld, in particular to a gas protection tool and a protection method on the back of a pipe and a tube plate, and belongs to the field of welding tool technology. The invention relates to a backside gas protection tooling for the welding of tubes and tube sheets. One end of the tooling is a tapered elastic centering clip that can be inserted and fixed in the tube, and the other end is an end that can be closely attached to the end of the tube. The end cover is connected with the elastic centering clip through a constriction to form an annular groove. A blind hole penetrating the constriction is opened from the outside of the end cover, and a vent hole is opened on the constriction. The vent hole will blindly The hole communicates with the annular groove. When the pipe and tube sheet are welded with the invention, the back of the weld (inner wall of the pipe) can be protected by the shielding gas, and the shielding gas can be saved; at the same time, the weld between the pipe and the tube sheet can form a good protective atmosphere, so that The weld seam is more beautiful and excellent.

Description

A kind of back gas protection tooling and protection method for pipe and tube sheet welding

technical field

The invention relates to a gas protection tool and a protection method at the back of a weld, in particular to a gas protection tool and a protection method for the back side of a pipe and a tube plate, and belongs to the field of welding tool technology.

Background technique

When the pipe is welded to the tube sheet, it is usually a fillet weld structure. When the pipe is a relatively active metal pipe such as a nickel-based alloy pipe, a stainless steel pipe, or a titanium and titanium alloy pipe. During the welding process, in order to prevent the back of the weld (that is, the inner wall of the pipe where the pipe and the tube sheet are welded) from being oxidized by high temperature and affect the corrosion resistance of the pipe, it is necessary to pass a shielding gas on the back of the weld (the shielding gas is preferably inert gas, such as argon).

In the prior art, the usual method is: as shown in Figure 1, when the tube and the tube sheet are assembled and welded, one end of the tube is welded with the tube sheet, and the other end of the tube is continuously injected with a shielding gas, and the shielding gas will The air in the tube is discharged, so that the back of the weld is under the protection of the shielding gas, thereby preventing the back of the weld from being oxidized by high temperature. However, the disadvantage of the above method is that: because the shielding gas needs to replace the air inside the whole pipe, and it needs to continuously inject the shielding gas that fills the inside of the pipe, this causes a waste of shielding gas; After the outflow, it will intersect with the protective gas flowing out of the welding torch (the air flow direction is opposite), which will easily destroy the protective atmosphere of the weld (that is, the weld between the tube and the tube sheet), thus affecting the protective effect of the weld.

Contents of the invention

The purpose of the present invention is to solve the above-mentioned problems and provide a backside gas shielding tooling and protection method for the welding of pipes and tube sheets. Gas; at the same time, the weld between the tube and the tube sheet can form a good protective atmosphere, making the weld more beautiful and excellent.

The technical scheme that the present invention adopts is as follows:

The utility model relates to a backside gas shielding tool for welding a tube and a tube sheet. One end of the tool is a tapered elastic centering clip that can be inserted and fixed in the tube, and the other end is an end cap that can fit closely with the end of the tube. The end cover and the elastic centering clip are connected through a constriction to form an annular groove. A blind hole is opened from the outside of the end cover to penetrate the constriction, and a vent hole is opened on the constriction. The vent hole connects the blind hole with the annular groove. The grooves are connected.

When the pipe and the tube plate are welded using the tooling of the present invention, push the elastic centering clip by hand and insert it into the pipe nozzle of the end to be welded, and at the same time push the tooling into the tube until the end cap is attached to the end of the tube. Under the action of the spring force of the elastic centering clip, the tooling is fixed inside the pipe, and at the same time, the elastic centering clip is used to ensure that the elastic centering clip and the pipe are basically concentric, so that the end cap and the pipe fit closer and more securely. Not easy to loosen. At this time, the annular groove is located on the back of the pipe and the tube plate to be welded, and forms an annular cavity with the inner wall of the pipe; the blind hole faces outside the pipe mouth of the pipe to be welded. Then, the protective gas is continuously injected into the blind hole through the external gas delivery pipe (the protective gas is preferably an inert gas, such as argon), and the protective gas flows into the annular cavity from the vent hole, so that the protective gas keeps filling the entire annular cavity and maintains positive pressure, to prevent air intrusion, and to prevent the end cover from loosening, so that the back of the place to be welded is under the protection of the protective gas, and the welding operation of the tube and the tube sheet can be carried out; after the welding is completed, only the tooling needs to be removed from the The tube can be pulled out to weld the next tube to the tube sheet, which is convenient and practical. Since the volume of the annular cavity is much smaller than the volume of the inner cavity of the entire pipe, the amount of protective gas can be greatly reduced and the protective gas can be saved. Since the end cap is closely attached to the end of the pipe, the shielding gas on the back of the weld will basically not flow out of the pipe nozzle at the weld end, which can avoid the occurrence of damage to the protective atmosphere of the shielding gas of the weld. And thanks to the existence of the end cap, the end of the tube forms a continuous entity (equivalent to the end cap sealing the nozzle of the tube), so that the protective gas of the weld between the tube and the tube sheet can form a complete "bell jar shape". That is, the end cap and the end of the pipe are tightly fitted, which can prevent the protective gas from the nozzle of the welding torch from drifting unimpeded, which is conducive to the formation of a "bell-shaped" protective atmosphere, effectively protecting the welding pool, and forming a better protection for the weld , making the weld shape more beautiful and the weld quality better. Obviously, one end of the elastic centering clip is the connection end connected to the constriction, the diameter of the connection end is smaller than the inner diameter of the pipe, and the other end is a free end, and the diameter of the free end in the free state (relaxed state) is slightly larger than the inner diameter of the pipe. It is used to insert and fix the tooling in the pipe.

The invention relates to a backside gas shielding frock for welding a tube and a tube sheet. The elastic centering clamp includes a connection part connected to the constriction, and a plurality of tapered elastic pieces connected to the connection part. As a preferred specific design of the elastic centering clamp, obviously, at this time, the annular groove is formed by connecting the end cover and the connecting part through a constriction. The design is simple in structure and easy to implement.

Preferably, there are four elastic sheets, and the cross section of the elastic sheets is arc-shaped.

The invention relates to a backside gas shielding tool for welding a tube and a tube sheet. There are a plurality of ventilation holes, which are arranged in a circular array and evenly distributed in the circumferential direction of the constriction. The shielding gas can evenly flow into and fill the annular cavity.

The invention relates to a backside gas shielding tool for welding a tube and a tube plate, the diameter of the end cap is slightly smaller than the outer diameter of the tube. That is, the diameter of the end cap is between the outer diameter and the inner diameter of the pipe, and the diameter of the end cap is closer to the outer diameter of the pipe. It can better make the end cap fit closely with the end of the pipe, not only does not hinder the operation of the welding torch, but also facilitates the observation of the molten pool.

The invention relates to a backside gas protection tooling for welding a tube and a tube plate, and the tooling has an integrated structure.

The invention relates to a backside gas protection tool for welding a tube and a tube plate. The end cover and the constriction are integrally formed, and the elastic centering clip is detachably connected to the constriction.

The invention relates to a backside gas protection tool for welding a tube and a tube plate, wherein the blind hole is connected with an air guide tube. It is convenient for the external gas pipeline to connect with the blind hole and inject protective gas.

Further, the air duct is connected with a pneumatic quick connector. It is convenient to connect the external air delivery tube to the air guide tube.

A gas shielding method for backside welding of a pipe and a tube sheet, comprising the following steps: adopting the above-mentioned tooling, inserting and fixing the tooling into the tube at the place to be welded; The back of the place, and forms an annular cavity with the inner wall of the pipe. The blind hole of the tooling faces outside the nozzle of the pipe to be welded, and the end cap is closely attached to the end of the pipe; the blind hole of the tooling continues into the annular cavity. Inject protective gas to keep the protective gas filling the entire annular cavity, and maintain a positive pressure of the protective gas to prevent air intrusion from damaging the protective effect. Thanks to the design of the annular groove and the annular cavity, the back of the weld (inner wall of the pipe) can be protected by shielding gas (such as argon), and the shielding gas can be saved; the end cap fits tightly with the end of the pipe , the shielding gas on the back of the weld will basically not flow out of the pipe nozzle at the welding end, which can avoid the occurrence of damage to the protective atmosphere of the shielding gas of the weld, and can prevent the argon gas sprayed from the nozzle of the welding torch from drifting unhindered, which is conducive to the formation of similar The "bell-shaped" protective atmosphere can effectively protect the welding pool and form a better protection for the weld, making the weld shape more beautiful and the quality of the weld better.

In summary, owing to adopting above-mentioned technical scheme, the beneficial effect of the present invention is:

The backside gas protection tooling for the welding of tubes and tube plates of the present invention has a simple structure, is easy to realize, is convenient to operate, is convenient to manufacture, has strong practicability, and is conducive to popularization and application; when the tubes and tube plates are welded using the invention, the The back of the weld (the inner wall of the pipe) is protected by the shielding gas, and the shielding gas can be saved; at the same time, the weld between the pipe and the tube sheet can form a good protective atmosphere, making the weld more beautiful and excellent.

Description of drawings

The invention will be illustrated by way of example with reference to the accompanying drawings, in which:

Fig. 1 is a schematic diagram of the flow direction of the shielding gas at the back of the weld in the prior art;

Fig. 2 is the sectional view of frock of the present invention;

Fig. 3 is the sectional view that the frock of the present invention is installed in the pipe;

Fig. 4 is a sectional view along A-A in Fig. 3 (not including the tube sheet).

Marks in the figure: 1-end cap, 2-neck, 21-blind hole, 22-ventilation hole, 23-ring groove, 3-elastic centering clip, 31-connecting part, 32-elastic piece, 4-guide Trachea, 41-pneumatic quick connector, 5-pipe, 51-annular cavity, 6-tube plate.

Detailed ways

All features disclosed in this specification, or steps in all methods or processes disclosed, may be combined in any manner, except for mutually exclusive features and/or steps.

Any feature disclosed in this specification, unless specifically stated, can be replaced by other alternative features that are equivalent or have similar purposes. That is, unless expressly stated otherwise, each feature is one example only of a series of equivalent or similar features.

Example 1

As shown in Fig. 2 to Fig. 4, a kind of backside gas shielding frock for pipe and tube sheet welding according to this embodiment, one end of the frock is a tapered elastic centering clip 3 which can be inserted and fixed in the pipe, and the other end is It is an end cap 1 that can fit closely with the end of the pipe. The end cap 1 is connected with the elastic centering clip 3 through a constriction 2 and forms an annular groove 23. A penetrating constriction 2 is opened from the outside of the end cap 1 The blind hole 21 is provided, and a ventilation hole 22 is opened on the constriction 2, and the ventilation hole 22 communicates the blind hole 21 with the annular groove 23.

When the pipe 5 and the tube plate 6 are welded using the tooling of the present invention, the elastic centering clip 3 is pushed by hand and inserted into the nozzle of the pipe 5 at the end to be welded, and the tooling is pushed into the pipe 5 at the same time until the end cover 1 and the The ends of the pipe 5 are fitted together, and under the elastic force of the springback of the elastic centering clip 3, the tooling is fixed inside the pipe 5. At the same time, the elastic force of the elastic centering clip 3 is used to effectively ensure that the elastic centering clip 3 and the pipe are basically Concentric, so that the end cap 1 and the pipe 5 fit closely and are not easy to loosen. At this time, the annular groove 23 is located at the back of the pipe 5 and the tube plate 6 to be welded, and forms an annular cavity 51 with the inner wall of the pipe 5; the blind hole 21 faces outside the pipe mouth of the pipe to be welded. Then continuously inject protective gas into the blind hole 21 through the external gas delivery pipe (the protective gas is preferably an inert gas, such as argon), and the protective gas flows into the annular cavity 51 from the vent hole 22, so that the protective gas keeps filling the entire annular cavity 51, and maintain a positive pressure to prevent air intrusion and prevent the end cover 1 from loosening, so that the back of the place to be welded is under the protection of the protective gas, and the welding operation of the tube 5 and the tube sheet 6 can be carried out; the welding is completed Finally, only the tooling needs to be pulled out from the pipe 5, and the welding operation of the next pipe and the tube sheet can be carried out, which is convenient and practical. Since the volume of the annular cavity 51 is much smaller than the volume of the inner cavity of the entire pipe 5, the amount of protective gas can be greatly reduced and the protective gas can be saved. Since the end cap 1 is closely attached to the end of the pipe 5, the shielding gas on the back of the weld will basically not flow out from the nozzle of the pipe at the weld end, which can avoid damaging the protective atmosphere of the shielding gas on the front of the weld (even if there is a small amount of overflow , and will not destroy the protective atmosphere of the weld); the elastic centering clip 3 has a gap, and the protective gas on the back of the weld passes through the gap in the annular cavity 51 and flows out through the non-welding end of the pipe 5. And thanks to the existence of the end cover 1, the end of the tube 5 forms a continuous entity (equivalent to the end cover 1 sealing the nozzle of the tube 5, which is not transparent), so that the protective gas of the weld between the tube and the tube sheet is not easy Floating can form a complete "bell shape". That is, the end cap 1 and the end of the pipe 5 are tightly fitted, which can prevent the protective gas sprayed from the nozzle of the welding torch from drifting unhindered, which is conducive to the formation of a "bell-shaped" protective atmosphere, effectively protecting the welding pool, and forming a better weld seam The protection makes the weld shape more beautiful and the weld quality better. Preferably, the tooling is made of stainless steel. Obviously, one end of the elastic centering clip 3 is a connection end connected to the constriction 2, the diameter of the connection end is smaller than the inner diameter of the pipe 5, and the other end is a free end, and the diameter of the free end is larger than the inner diameter of the pipe 5 in a free state. Preferably, the end of the free end is provided with a reduced-diameter tapered section smaller than the inner diameter of the pipe 5, so as to facilitate the insertion of the elastic centering clip 3 into the pipe 5 and play a guiding role.

Based on the further optimization of this embodiment, as shown in Fig. 2 and Fig. 3, in another embodiment, the elastic centering clip 3 includes a connection part 31 connected to the constriction 2, and a connection part 31 connected to the connection part 31 A plurality of tapered elastic pieces 32. As a preferred specific design of the elastic centering clip 3 , the connecting portion 31 is connected with a plurality of elastic pieces 32 to form a tapered elastic centering clip 3 . Obviously, at this time, the annular groove 23 is formed by the connection between the end cap 1 and the connecting portion 31 through the constriction 2 . The design is simple in structure and easy to implement. Obviously, the diameter of the connecting part 31 is smaller than the inner diameter of the pipe 5, the diameter of the end connected to the connecting part 32 of the elastic sheet 32 is smaller than the inner diameter of the pipe 5, and the other end of the elastic sheet 32 is a free end, which is in a free state (relaxed state) The lower outer diameter is slightly larger than the inner diameter of the pipe 5, so that the tooling can be fixed in the pipe 5 through the elastic centering clip 3. When adopting this design and using the tooling, push the elastic piece 32 by hand and insert it into the nozzle of the pipe 5 at the end to be welded, and push the tooling into the tube 5 at the same time until the end cap 1 and the end of the tube 5 are attached, and the Under the elastic force of the rebound of the sheet 32, together with the end cover 1, the elastic centering clip 3 is coaxial with the pipe 5, so that the tooling is fixed inside the pipe 5. The connecting portion 31 and the elastic piece 32 can be integrally formed, or the elastic piece 32 can be welded to the connecting portion 31 . Preferably, the end of the elastic piece 32 far away from the connecting portion 31 is provided with a tapered tapered section (not labeled, as shown in Figure 2 and Figure 3 ) smaller than the inner diameter of the pipe 5, so as to facilitate the insertion of the elastic centering clip 3 into the pipe 5 and Play a guiding role.

Further, as shown in FIG. 2 to FIG. 4 , in another embodiment, there are four elastic pieces 32 ; of course, there may be two, three, five or more pieces. Preferably, the section of the elastic piece 32 is arc-shaped, so that the elastic centering clip 3 forms a conical shape, so that the elastic piece 32 fits the inner wall of the pipe 5 . Preferably, in one of the embodiments, there are four elastic pieces 32, and the cross section of the elastic pieces 32 is arc-shaped. At this time, the elastic centering clip 3 is a cross centering spring structure, and each elastic piece 32 is in a circular array It is obvious that there are gaps between each elastic piece 32, as the overflow channel of the protective gas, its total cross-sectional area is slightly smaller than the total cross-sectional area of the vent hole 22, so as to facilitate the formation of positive pressure of the protective gas and prevent Air intrusion reduces the protective effect.

Based on the further optimization of this embodiment, in another embodiment, there are a plurality of vent holes 22, which are arranged in a circular array and evenly distributed in the circumferential direction of the constriction 2 . The shielding gas can evenly flow into and fill the annular cavity 51 . As shown in FIG. 4 , in one embodiment, there are six air holes 22 ; of course, there may be only one air hole 22 , or there may be two, three, four, five or seven more air holes.

Based on further optimization of this embodiment, as shown in FIG. 2 , in another embodiment, the diameter of the end cap 1 is slightly smaller than the outer diameter of the pipe 5 . That is, the diameter of the end cap 1 is between the outer diameter and the inner diameter of the pipe 5 , and the diameter of the end cap 1 is closer to the outer diameter of the pipe 5 . It can better make the end cap 1 and the end of the pipe 5 (the end surface of the pipe nozzle) fit closely, which will not hinder the operation of the welding torch, but also facilitate the observation of the molten pool. Of course, it can also be: the diameter of the end cap 1 is slightly larger than the outer diameter of the pipe 5 to be assembled and welded; it can also be: the diameter of the end cap 1 is slightly smaller than the inner diameter of the pipe 5 to be assembled and welded. Inside the pipe 5, the outer peripheral wall of the end cap 1 fits the end of the pipe (the inner wall of the pipe mouth).

Based on further optimization of this embodiment, as shown in FIG. 3 , in another embodiment, the tooling is an integrally formed structure.

Based on the further optimization of this embodiment, as shown in Figure 2, in another embodiment, the end cap 1 and the constriction 2 are integrally formed, and the elastic centering clip 3 is detachable with the constriction 2 connected. Specifically, the elastic centering clip 3 is connected to the constricted neck 2 through a thread connection or a bolt connection. Of course, the elastic centering clip 3 can also be connected to the constriction 2 by welding.

Based on further optimization of this embodiment, as shown in FIG. 3 , in another embodiment, the blind hole 21 is connected with an air duct 4 . The gas pipeline convenient for external connection is connected with the blind hole 21, and the protective gas is injected. Preferably, the air guide tube 4 is connected to the blind hole 21 through a threaded connection, of course, it can also be connected through welding. Preferably, as shown in FIG. 3 , in another embodiment, the air duct 4 is L-shaped. During the welding process, the air guide tube 4 will inevitably block part of the front weld seam, making the welding operation inconvenient; and thanks to the design of the L-shaped air guide tube 4, it is convenient for the welder to push the air guide tube 4 apart by hand, which is convenient Welding.

Further, as shown in FIG. 3 , in another embodiment, the air duct 4 is connected with a pneumatic quick connector 41 . The gas delivery tube that is convenient for external connection is connected on the air guide tube 4 . Preferably, the pneumatic quick connector 41 is connected to the airway tube 4 through threaded connection.

Example 2

A backside gas shielding method for welding a tube and a tube sheet in this embodiment comprises the following steps: using the tooling in Example 1, and inserting and fixing the tooling into the pipe 5 at the place to be welded; the ring shape of the tooling The groove 23 is located at the back of the pipe 5 and the tube plate 6 to be welded, and forms an annular cavity 51 with the inner wall of the pipe 5. The blind hole 21 of the tooling faces outside the nozzle of the pipe 5 to be welded, and the end cap 1 and the pipe 5 The ends are tightly fitted; the protective gas is continuously injected into the annular cavity 51 from the blind hole 21 of the tooling, so that the protective gas keeps filling the entire annular cavity 51, and the protective gas maintains a certain positive pressure to prevent air from invading and damaging the protection. Effect. Thanks to the design of the annular groove 23 and the annular cavity 51, the back of the weld (inner wall of the pipe) can be protected by a shielding gas (such as argon), and the shielding gas can be saved; the end cap 1 and the end of the pipe 5 The shielding gas on the back of the welding seam will basically not flow out from the nozzle of the pipe 5 at the welding end, which can avoid damage to the protective atmosphere of the shielding gas of the welding seam, and can prevent the shielding gas sprayed from the welding torch nozzle from drifting unimpeded , which is conducive to the formation of a "bell-shaped" protective atmosphere, effectively protecting the welding pool, forming a better protection for the weld, making the weld shape more beautiful and the weld quality better.

To sum up, the backside gas shielding tooling for pipe and tube plate welding of the present invention has a simple structure, is easy to realize, is convenient to operate, is convenient to manufacture, has strong practicability, and is conducive to popularization and application. When the pipe and the tube sheet are welded using the present invention, the back of the weld (the inner wall of the pipe) can be protected by the shielding gas, and the shielding gas can be saved; at the same time, the weld between the pipe and the tube sheet can form a good protective atmosphere, Make the weld more beautiful and excellent.

The present invention is not limited to the foregoing specific embodiments. The present invention extends to any new feature or any new combination disclosed in this specification, and any new method or process step or any new combination disclosed.

Claims (10)

1. A kind of 1. backside gas protecting tool set-up that tube-to-tube sheet connection mutually welds, it is characterised in that：The frock one end is pluggable and solid Due to elastic centering folder tapered in pipe（3）, the other end be the end cap that can be brought into close contact with tube end（1）, the end cap （1）Pressed from both sides with elastic centering（3）Between pass through necking down（2）It is connected and forms annular groove（23）, from end cap（1）Outside, which offers, wears Enter necking down（2）Blind hole（21）, and necking down（2）On offer passage（22）, the passage（22）By blind hole（21）With annular Groove（23）Connection.
2. 2. the backside gas protecting tool set-up that a kind of tube-to-tube sheet connection as claimed in claim 1 mutually welds, it is characterised in that：The bullet Property centering folder（3）Including with necking down（2）Connected connecting portion（31）And it is connected to connecting portion（31）On multiple there is taper Flexure strip（32）.
3. 3. the backside gas protecting tool set-up that a kind of tube-to-tube sheet connection as claimed in claim 2 mutually welds, it is characterised in that：The bullet Property piece（32）There are 4, flexure strip（32）Section it is curved.
4. 4. the backside gas protecting tool set-up that a kind of tube-to-tube sheet connection as claimed in claim 1 mutually welds, it is characterised in that：It is described logical Stomata（22）Have multiple, and circumferentially array is distributed in necking down（2）On circumferencial direction.
5. 5. the backside gas protecting tool set-up that a kind of tube-to-tube sheet connection as claimed in claim 1 mutually welds, it is characterised in that：The end Lid（1）Diameter be slightly less than pipe（5）External diameter.
6. 6. the backside gas protecting tool set-up that a kind of tube-to-tube sheet connection as claimed in claim 1 mutually welds, it is characterised in that：The frock Be formed in one structure.
7. 7. the backside gas protecting tool set-up that a kind of tube-to-tube sheet connection as claimed in claim 1 mutually welds, it is characterised in that：The end Lid（1）With necking down（2）Be formed in one structure, the elastic centering folder（3）Removably and necking down（2）It is connected.
8. 8. the backside gas protecting tool set-up that a kind of tube-to-tube sheet connection as claimed in claim 1 mutually welds, it is characterised in that：It is described blind Hole（21）On be connected with airway tube（4）.
9. 9. the backside gas protecting tool set-up that a kind of tube-to-tube sheet connection as claimed in claim 8 mutually welds, it is characterised in that：It is described to lead Tracheae（4）On be connected with Pneumatic quick connector（41）.
10. 10. the backside gas guard method that a kind of tube-to-tube sheet connection mutually welds, it is characterised in that comprise the following steps：

    It is inserted and fixed using the frock as described in claim any one of 1-9, and by the frock in the pipe at place to be welded（5） It is interior；

    The annular groove of the frock（23）Positioned at pipe（5）With tube sheet（6）The back side at place to be welded, and and pipe（5）Inwall shape Circularize cavity（51）, the blind hole of the frock（21）Towards the pipe at place to be welded（5）Outside the mouth of pipe, and end cap（1）With pipe（5） End is brought into close contact；

    From the blind hole of the frock（21）To annular housing（51）Interior lasting injection protective gas, remains full of protective gas whole Individual annular housing（51）, and protective gas is kept malleation.