CN116336280A

CN116336280A - Corrugated metal hose based on braze welding in furnace

Info

Publication number: CN116336280A
Application number: CN202310504909.XA
Authority: CN
Inventors: 孙一奇
Original assignee: Zhuji Sbeda Metal Co ltd
Current assignee: Zhuji Sbeda Metal Co ltd
Priority date: 2023-05-04
Filing date: 2023-05-04
Publication date: 2023-06-27

Abstract

The invention provides a corrugated metal hose based on braze welding in a furnace, which comprises a corrugated pipe, a reinforcing sleeve, a connecting pipe, a net sleeve sleeved outside the corrugated pipe and an outer sleeve wrapping the end part of the net sleeve. Limiting parts are formed on the two circular tube-shaped connecting sections of the corrugated tube. The manufacturing method of the corrugated metal hose comprises the following steps: sleeving the reinforcing sleeve on the circular pipe-shaped connecting section to form a welding section for welding the connecting pipe; a limiting part for limiting the axial displacement of the reinforcing sleeve relative to the circular pipe-shaped connecting section in the direction pointing to the port of the circular pipe-shaped connecting section is processed on the circular pipe-shaped connecting section; fixing the welding section through a tool to press the connecting pipe into the welding section; the reinforcing sleeve and the connecting pipe are assembled on the other circular pipe-shaped connecting section by adopting the working procedure steps; solder is placed at the welding seam between the inner peripheral wall of the circular pipe-shaped connecting section and the outer peripheral wall of the connecting pipe, and at the welding seam between the outer peripheral wall of the circular pipe-shaped connecting section and the inner peripheral wall of the reinforcing sleeve; and (3) performing furnace brazing on the assembled part subjected to the working procedures.

Description

Corrugated metal hose based on braze welding in furnace

Technical Field

The present invention relates to piping systems and in particular to a corrugated metal hose based on braze in a furnace.

Background

The corrugated metal hose is a hose for compensating displacement and installation deviation, absorbing vibration and reducing noise in a pipeline system, and is widely applied to the industries of refrigeration, petrochemical industry, steel and the like, transportation and the like. The traditional corrugated metal pipe mainly comprises a corrugated pipe, a net sleeve, an inner bushing, an outer bushing and a copper joint. Wherein the bellows, the inner bushing and the copper joint are three-in-one brass flame brazed to form two weld joints A1, A2; and then the outer bushing, the net sleeve and the inner bushing are connected (A3) through argon arc welding, as shown in figure 1. Because the corrugated pipe is made of a thin-wall stainless steel material, oxidation is very easy to generate during flame brazing, and even if soldering flux is added, the oxidation cannot be completely avoided, so that the welding problems such as cold joint or broken joint and the like of the welding line are caused; and the three-in-one welding forms two welding seams, so that the welding difficulty is great, and the quality of the welding seams is further difficult to ensure. In addition, the welding seam formed by flame brazing has a low melting point, and when the corrugated metal hose is subsequently flame brazed with a system pipeline, the welding seam is extremely easy to generate secondary welding and melting to cause leakage.

In order to solve the problem of high welding difficulty of the traditional corrugated metal hose, an improved corrugated metal hose is proposed. As shown in fig. 2, the inner bush is a turning piece, one end of the turning piece is connected with a corrugated pipe and then is brazed in the furnace (at a position B1), and then argon arc welding is carried out on the outer bush, the net sleeve and the inner bush (at a position B2); finally, the copper tube is connected to the inner liner for flame brazing (at B3). Although the structure takes the turned inner bushing as a transition piece to realize step-by-step welding so as to reduce the welding difficulty, the structure still has the problem of low quality of welding seams after flame brazing of stainless steel products. And furthermore, the inner bushing structure turned in the structure is complex in process, high in processing difficulty and low in processing efficiency. To further solve the problems caused by flame brazing, chinese patent CN108526636B proposes a corrugated metal hose welded in an integral furnace. In the structure, the connecting sections of the corrugated pipes are welded at the matching parts of the adapting pieces on the corresponding sides, and the inserted thin-wall corrugated pipes are deformed after being brazed in a high-temperature long-time furnace, so that the welding gap is uneven, and the welding qualification rate is seriously affected. In addition, the inner liner still employs turning pieces that are difficult to machine in this configuration.

In order to solve the problems of high processing difficulty, low efficiency and the like caused by turning the inner bushing, a metal hose structure formed by bending and rolling the inner bushing is disclosed in Chinese patent CN218883236U, and the metal hose can also be integrally welded and formed in a furnace. Although the structure effectively solves the problems caused by turning the inner bushing, in the structure, the corrugated pipe is positioned at the innermost side, and the brazing in the furnace still can lead to the deformation of the thin-wall corrugated pipe so as to solve the problems of uneven welding gap and low welding qualification rate. In addition, because the welding flux can infiltrate between the net cover and the corrugated pipe during brazing in the integrated furnace, the solidified welding flux layer can harden the corrugated metal hose, and therefore the static bending performance and the dynamic bending performance of the corrugated metal hose are difficult to meet the standard requirements.

In addition, chinese patent CN218348154U proposes a corrugated shock absorber for improving the quality of the weld by providing a step on the adapter tube. In this structure, the provision of two steps makes welds formed between the first step portion and the bellows, between the bellows and the steel bushing, and between the second step portion and the steel bushing. The multi-weld joint communication structure causes the flow of the welding flux to have great randomness, and the welding flux is difficult to permeate according to design prediction in the actual welding process, so that the problems of insufficient welding, broken welding, uneven welding flux distribution and the like are very easy to occur in the necessary welding flux with the sealing requirement. Further, the multi-layer construction also presents a problem in that the layer-to-layer gap is difficult to control. In addition, the structure has the problem of difficult assembly; specifically, in the structure, the connecting pipe, the corrugated pipe and the steel bushing are required to be sleeved in sequence, but the whole product does not have any limit position.

Disclosure of Invention

The present invention aims to overcome at least one of the disadvantages of the prior art by providing a corrugated metal hose based on braze in a furnace.

In order to achieve the above object, the present invention provides a corrugated metal hose based on braze welding in a furnace, which comprises a corrugated pipe, a reinforcing sleeve, a connecting pipe, a net sleeve sleeved outside the corrugated pipe and an outer sleeve covering the end part of the net sleeve; the corrugated pipe comprises a corrugated section in the middle and two circular pipe-shaped connecting sections positioned at two ends of the corrugated section, and each circular pipe-shaped connecting section is provided with a limiting part;

the manufacturing method of the corrugated metal hose based on furnace brazing comprises the following steps:

sleeving the reinforcing sleeve on the circular pipe-shaped connecting section of the corrugated pipe to form a welding section for welding the connecting pipe;

a limiting part for limiting the axial displacement of the reinforcing sleeve relative to the circular pipe-shaped connecting section in the direction pointing to the port of the circular pipe-shaped connecting section is processed on the circular pipe-shaped connecting section;

fixing the welding section through a tool to press the connecting pipe into the welding section;

the reinforcing sleeve and the connecting pipe are assembled on the other circular pipe-shaped connecting section of the corrugated pipe by adopting the working procedure steps;

solder is placed at the welding seam between the inner peripheral wall of the circular pipe-shaped connecting section and the outer peripheral wall of the connecting pipe, and at the welding seam between the outer peripheral wall of the circular pipe-shaped connecting section and the inner peripheral wall of the reinforcing sleeve;

and (3) performing furnace brazing on the assembled part subjected to the working procedures.

According to an embodiment of the invention, the bellows connecting section is internally expanded after the sleeve is sleeved with the reinforcing sleeve so as to tightly fit the bellows connecting section and the reinforcing sleeve.

According to one embodiment of the invention, a flaring or flanging-shaped limit part is processed at the port of the circular pipe-shaped connecting section at the same time of internal expansion or after the internal expansion is finished;

or forming a limit part at the inner wall of the circular tube-shaped connecting section in a manner of forming convex points or convex ribs radially outwards after the internal expansion is finished;

or the limit part is formed by welding the circular tube-shaped connecting section and the reinforcing sleeve after the internal expansion is finished.

According to an embodiment of the invention, when the limiting part is in a flaring shape or a flanging shape, solder is respectively placed on the inner side and the outer side of the limiting part, and the solder on the inner side permeates into a welding seam between the inner peripheral wall of the circular pipe-shaped connecting section and the outer peripheral wall of the connecting pipe; the welding flux on the outer side permeates into the welding seam between the outer peripheral wall of the circular pipe-shaped connecting section and the inner peripheral wall of the reinforcing sleeve.

According to an embodiment of the invention, the liquidus of the placed braze is not lower than 950 degrees celsius.

According to an embodiment of the present invention, the method for manufacturing a corrugated metal hose based on furnace brazing further comprises:

sleeving the net cover outside the brazed assembly in the furnace;

fixing the net sleeve and the reinforcing sleeve by adopting a self-melting welding or mechanical connection mode;

the two ends of the net sleeve are respectively sleeved with the outer sleeve and are in compression joint with the net sleeve through the reducing.

sleeving the net cover outside the brazed assembly in the furnace;

sleeving an outer sleeve at two ends of the net sleeve respectively to cover the two ends of the net sleeve;

and the reinforcement sleeve, the net sleeve and the outer sleeve are welded by adopting argon arc welding or laser welding.

According to an embodiment of the invention, a plurality of axially extending wire drawing lines or knurls are distributed on the peripheral wall of the end of the adapter tube connected with the circular tube-shaped connecting section.

According to an embodiment of the present invention, the adapter is any one of a quick-joint type, a pipe screw type, a flange type, or an adapter type.

According to an embodiment of the invention, the adapter tube is a copper tube or a stainless steel tube; alternatively, the adapter tube is an assembly of copper tube and stainless steel tube.

According to an embodiment of the invention, the welding insertion depth L of the adapter tube and the circular tube-shaped connecting section satisfies: l is more than or equal to 0.2D and less than or equal to 0.7D; wherein D is the outer diameter of the straight section of the upper main body of the connecting pipe.

In summary, in the corrugated metal hose based on braze welding in a furnace provided by the invention, the reinforcing sleeve is sleeved outside the circular pipe-shaped connecting section of the corrugated pipe so as to support the outer peripheral wall of the circular pipe-shaped connecting section and limit the deformation space of the circular pipe-shaped connecting section in the radial direction during braze welding in the furnace. The connecting pipe is inserted in the circular pipe-shaped connection and is inserted into the welding section, and the connecting pipe and the reinforcing sleeve clamp the circular pipe-shaped connection section from the inner side and the outer side so as to effectively solve the problem that the welding gap is uneven due to deformation of the circular pipe-shaped connection section when the circular pipe-shaped connection section is brazed in a furnace. The limiting part is formed on the circular pipe-shaped connecting section, and the limiting part limits the axial displacement of the reinforcing sleeve relative to the circular pipe-shaped connecting section in the direction pointing to the port of the circular pipe-shaped connecting section when the connecting pipe is inserted, so that the connecting pipe is assembled. Meanwhile, the limiting part effectively isolates the two welding seams on the inner peripheral wall side and the outer peripheral wall side of the circular tube-shaped connecting section, so that welding fluxes placed at the two welding seams can respectively permeate into the corresponding welding seams in a directional manner, enough welding fluxes are guaranteed to permeate into key welding seams between the inner peripheral wall of the circular tube-shaped connecting section and the outer peripheral wall of the connecting tube after welding, the welding fluxes are uniformly distributed, and the welding quality problems of broken welding, flow welding, virtual welding and the like caused by random flow of the welding fluxes due to the communication of a plurality of welding seams are effectively solved. In addition, the spacing portion also provides space for solder to be placed so that the solder can be placed stably, provides basic conditions for the solder to infiltrate into corresponding welding seams, and simultaneously greatly reduces the difficulty of solder assembly.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments, as illustrated in the accompanying drawings.

Drawings

Fig. 1 and 2 are schematic structural views of a conventional corrugated metal hose.

Fig. 3 is a schematic view showing a structure of a corrugated metal hose based on brazing in a furnace according to an embodiment of the present invention.

Fig. 4 shows a schematic view of the assembly of the bellows and the mesh in fig. 3.

Fig. 5 is an enlarged schematic view of fig. 3 at C.

Fig. 6 is a partial schematic view of the assembly of the stiffening sleeve and bellows of fig. 3.

Fig. 7 is a schematic diagram showing the stress analysis of the circular pipe-shaped connecting section clamped by the reinforcing sleeve and the connecting pipe.

Fig. 8 is a schematic diagram showing the assembly of the corrugated metal hose based on furnace brazing, which is provided by the invention, wherein a connecting pipe is pressed into a circular pipe-shaped connecting section.

Fig. 9 shows the direction of movement of the connecting tube and the reinforcement sleeve during the insertion of the connecting tube.

Fig. 10 is a schematic structural view of increasing the inner diameter of a circular tubular connecting section by using a conventional axial flaring process.

FIG. 11 is a schematic diagram showing the structure of the present invention using the radially integrally expanding the inner diameter of the tubular connecting section.

Fig. 12, 13, 14, 15 and 16 are schematic structural views of a limiting portion according to another embodiment of the present invention.

Fig. 17A is a schematic view of a connection pipe according to an embodiment of the present invention.

Fig. 17B, 17C and 17D are schematic views of a connection pipe structure according to another embodiment of the present invention.

Fig. 18 is a schematic view of a quick connector adapter according to another embodiment of the present invention.

Fig. 19A is a schematic view of a flange-type adapter according to another embodiment of the present invention.

Fig. 19B is a schematic view of the structure of fig. 19A at another view angle.

Fig. 20A and 20B are schematic views of a pipe nipple according to another embodiment of the present invention.

Fig. 21 and 22 are schematic structural views of corrugated metal hoses based on braze in a furnace according to another embodiment of the present invention.

FIG. 23 is a schematic flow chart of a process for manufacturing a corrugated metal hose based on braze in a furnace according to an embodiment of the present invention.

Detailed Description

Both the traditional corrugated metal hose and the improved corrugated metal hose using the turning piece as the transition piece are welded by flame brazing. For corrugated pipes made of stainless steel materials, the welding seam after flame brazing is extremely easy to generate the welding problems of cold joint, broken joint, secondary welding and melting and the like, so that the hidden danger of welding exists. For this purpose, corrugated metal hoses have been proposed which improve the quality of the weld seam by means of brazing in a furnace or by providing steps on the adapter tube. For the corrugated metal hose brazed in the furnace, the problem that welding leakage is caused by uneven welding gaps due to deformation of the welded thin-wall corrugated pipe exists; the multi-step arrangement on the connecting pipe has the problems that a plurality of welding seams are communicated, so that the randomness of the flow of the welding flux is high, and the critical welding seam is in cold joint, broken joint, difficult assembly and the like.

In view of this, this embodiment provides a corrugated metal hose that is welded by an intensive in-furnace brazing process, and after welding, the thin-walled corrugated tube is not deformed, the key welds are full, and the solders are uniformly distributed.

As shown in fig. 3 to 6, the corrugated metal hose based on braze welding in a furnace provided in this embodiment includes a corrugated pipe 1, a reinforcing sleeve 2, a connection pipe 3, a mesh 4 that is externally sleeved on the corrugated pipe 1, and an outer sleeve 5 that covers the end of the mesh 4. The corrugated pipe 1 comprises a middle corrugated section 11 and two circular pipe-shaped connecting sections 12 positioned at two ends of the corrugated section 11, wherein a limiting part 121 is formed on each circular pipe-shaped connecting section 12, and the limiting part 121 limits the axial displacement of the reinforcing sleeve 2 relative to the circular pipe-shaped connecting sections 12 in the direction pointing to the port of the circular pipe-shaped connecting section 12. The two reinforcing sleeves 2 are respectively sleeved on the two circular tube-shaped connecting sections 12 of the corrugated tube 1, and the reinforcing sleeves 2 reinforce the circular tube-shaped connecting sections 12 to form a welding section 10 for welding the connecting tube. The two connection pipes 3 are respectively inserted into the two circular pipe-shaped connecting sections 12 of the corrugated pipe and are inserted into the welding section 10, and a solder layer 101 is formed between the connection pipes 3 and the circular pipe-shaped connecting sections 12.

Preferably, the welding insertion depth L of the connecting tube 3 and the circular tube-shaped connecting section 12 is set to be: l is more than or equal to 0.2D and less than or equal to 0.7D. Wherein D is the outer diameter of the main body straight section 30 on the adapter tube 3, and the main body straight section 30 refers to the straight section area of the adapter tube 3 which is not connected with the circular tube-shaped connecting section 12. The arrangement of the welding insertion depth of the connecting pipe 3 can ensure that the connecting pipe 3 has excellent welding strength after welding. However, the present invention is not limited in any way thereto.

In this embodiment, the two reinforcing sleeves 2 have the same structure, and are both formed by bending and rolling a lining plate. However, the present invention is not limited in any way thereto. In other embodiments, the reinforcing sleeve may also be obtained by blanking a circular tube; if the assembly precision of the reinforced sleeve after direct blanking can not meet the requirement, simple turning can be carried out to improve the assembly precision of the inner hole of the reinforced sleeve. Although this embodiment is described by taking two reinforcing sleeves as an example of the same structure. However, the present invention is not limited in any way thereto. In other embodiments, the two reinforcement sleeves may be configured differently, both of which may take any of the forms described above.

In this embodiment, the bellows 1 is made of a thin-walled stainless steel material, the two reinforcing sleeves 2 are made of a stainless steel material, and the two connecting pipes 3 are identical in structure and are stainless steel pipes. However, the present invention is not limited in any way thereto. In other embodiments, the two connection pipes may have different structures, and the materials of the two connection pipes may also be different according to the connection requirements of the external pipeline, for example, one connection pipe is a copper pipe, and the other connection pipe is a stainless steel pipe or a combination of a copper pipe and a stainless steel pipe; alternatively, both connecting pipes are copper pipes.

The processing process of the corrugated metal hose based on braze welding in the furnace provided by the embodiment comprises the following steps: the reinforcing sleeve 2 obtained after bending and rolling or blanking the circular pipe is sleeved on the circular pipe-shaped connecting section 12 of the corrugated pipe to form a welding section 10 for welding the connecting pipe (step S10). A limiting portion 121 for limiting the axial displacement of the reinforcing sleeve 2 relative to the circular tubular connecting section 12 in a direction pointing to the port of the circular tubular connecting section 12 is machined on the circular tubular connecting section 12 (step S20). The welded segment 10 is fixed by a tool to press the adapter tube 3 into the welded segment 10 (step S30). The above procedure steps are used to assemble a further reinforcement sleeve 2 and a further connection tube 3 on a further tubular connection section 12 of the bellows. Solder is placed at the weld between the inner peripheral wall of the circular pipe-shaped connecting section 12 and the outer peripheral wall of the adapter tube 3 and at the weld between the outer peripheral wall of the circular pipe-shaped connecting section 12 and the inner peripheral wall of the reinforcing sleeve 2 (step S40). The assembled product after the above steps is subjected to furnace brazing (step S50).

In the corrugated metal hose based on braze welding in the furnace provided by the embodiment, the reinforcing sleeve 2 is arranged outside the circular pipe-shaped connecting section 12, and the circular pipe-shaped connecting section 12 with the thin wall is supported by utilizing the rigidity of the reinforcing sleeve 2 so as to effectively avoid the deformation of the circular pipe-shaped connecting section 12 in the welding process. In particular, the high temperature and long time welding of the thin walled tubular connection section 12 results in deformation thereof during furnace brazing. At this time, as shown in fig. 7, the reinforcing sleeve 2 will generate a supporting force F1 directed toward the inner side of the circular tube-shaped connection section 12 to the circular tube-shaped connection 12 to prevent the circumferential wall of the circular tube-shaped connection section from being deformed convexly outward. Similarly, the connecting piece 3 inserted into the tubular connecting section 12 also generates an outward supporting force F2 on the tubular connecting section 12 when it is deformed. The opposite supporting forces F1 and F2 clamp the thin-walled circular tube-shaped connecting section 12, so that the welding flux permeation gaps of two welding seams (the welding seams between the inner peripheral wall of the circular tube-shaped connecting section 12 and the outer peripheral wall of the connecting tube 3 and the welding seams between the outer peripheral wall of the circular tube-shaped connecting section 12 and the inner peripheral wall of the reinforcing sleeve 2) on two sides of the circular tube-shaped connecting section 12 are uniformly distributed, and the leakage problem caused by uneven welding gap size due to the deformation of the thin-walled circular tube-shaped connecting section after the conventional corrugated metal hose is brazed in the furnace is well solved. In addition, the insertion of the adapter tube 3 during the assembly of the tubular connecting section 12 and the adapter tube 3 also deforms the tubular connecting section 12, and the reinforcing sleeve 2 also supports the tubular connecting section 12 in this step.

In this embodiment, the reinforcing sleeve 2, the circular tube-shaped connecting section 12 and the connecting tube 3 are sequentially assembled in a sleeved manner. Since the bellows 1 is made of a thin-walled stainless steel material and has the bellows 11, this structure will make it difficult to stably apply pressure in the axial direction to press into the adapter tube 3. The connection tube 3 is thus pressed into the tubular connecting section 12 in step S30 by means of a tool to fix the end of the reinforcement sleeve 2. Based on this positioning, when the adapter tube 3 is pressed in the direction indicated by the arrow K in fig. 8 and 9, the reinforcing sleeve 2 at the welding section 10 will move relative to the circular tube-shaped connecting section 12 in the direction of the port of the circular tube-shaped connecting section 12 (i.e., in the direction indicated by the arrow K' in fig. 9) to cause the reinforcing sleeve 2 to be separated from the circular tube-shaped connecting section 12. To solve this assembly problem, the present embodiment prevents the detachment of the reinforcing sleeve 2 during the assembly of the adapter tube 3 by forming the limiting portion 121 on the circular tube-shaped connecting section 12 to limit the axial displacement of the reinforcing sleeve 2 relative to the circular tube-shaped connecting section 12 in the direction pointing to the port of the circular tube-shaped connecting section 12 during the assembly of the adapter tube 3. The provision of the limiting portion 121 provides conditions for press fitting the adapter tube 3 of the bellows 1 without applying force, avoiding deformation of the bellows 1 during assembly.

Further, as shown in fig. 5 and 6, the stopper 121, which is bent, turned, or raised in the direction in which the reinforcing sleeve 2 is located, will effectively isolate the inner peripheral wall side weld (the weld between the inner peripheral wall of the tubular connecting section 12 and the outer peripheral wall of the adapter tube 3) and the outer peripheral wall side weld (the weld between the outer peripheral wall of the tubular connecting section 12 and the inner peripheral wall of the reinforcing sleeve 2) of the tubular connecting section 12. During welding, the welding flux between two welding seams is difficult to flow mutually over the surface of the bent, inclined or arc-shaped protruding limiting part. Namely, the solder placed on the inner peripheral wall side of the circular tube-shaped connecting section 12 only permeates into the welding seam between the inner peripheral wall of the circular tube-shaped connecting section 12 and the outer peripheral wall of the connecting tube 3; and the solder placed on the outer peripheral wall side of the circular tube-shaped connecting section 12 only penetrates into the weld between the outer peripheral wall of the circular tube-shaped connecting section 12 and the inner peripheral wall of the reinforcing sleeve 2. The spacing part 121 is isolated so that the solder does not have randomness in flowing between two communicating welding seams, the solder can directionally infiltrate to the welding seams corresponding to the welding seams, the uniform distribution of the solder in the key welding seams formed between the inner peripheral wall of the circular tube-shaped connecting section 12 and the outer peripheral wall of the connecting tube 3 is ensured, the welding seams after welding are full, and the welded corrugated metal hose has excellent welding strength and welding tightness. Further, the spacing portion 121 that bends, turns or bulges towards the direction of the reinforcement sleeve 2 also provides a holding space for placing solder, and the stable placement of solder is more beneficial to directional penetration of solder. Specifically, as shown in fig. 5 and 6, the limiting portion 121 has a flared shape, and has an inner side and an outer side each formed with a receiving groove for receiving solder, and the solder placed in the inner receiving groove 1211 permeates into the weld between the inner peripheral wall of the circular tube-shaped connecting section 12 and the outer peripheral wall of the adapter tube 3 to form the solder layer 101; solder placed in the outer accommodating groove 1212 penetrates into the weld between the outer peripheral wall of the circular tube-shaped connecting section 12 and the inner peripheral wall of the reinforcing sleeve 2 to form the solder layer 102.

Further, in order to make the molten solder better penetrate into the weld seam during welding, the corrugated metal hose based on furnace brazing provided in this embodiment has a plurality of wire drawing lines or knurls 310 extending along the axial direction distributed on the outer peripheral wall of the portion connected to the circular tube-shaped connecting section 12 on the connecting tube 3.

The processing steps of the corrugated metal hose based on brazing in a furnace according to the present embodiment will be described in detail with reference to the accompanying drawings.

As described above, the assembly of the reinforcing sleeve 2 in step S10 can effectively avoid the problem of uneven welding gap caused by deformation of the thin-walled tubular connecting section 12 after brazing in the furnace. It is therefore desirable to provide a transition fit between the reinforcing sleeve 2 and the tubular connecting section 12 when assembling the sleeve to meet solder penetration requirements. The transition fit means that the tolerance zone of the inner diameter of the reinforcing sleeve 2 and the tolerance zone of the outer diameter of the circular tube-shaped connecting section 12 overlap each other, and the two parts can be in clearance fit or interference fit, but the clearance and the interference are small. The small amount of clearance and interference limits the deformation space of the tubular connecting section 12 so that it is not easily deformed during brazing in the furnace to affect the welding gap between the inner peripheral wall of the tubular connecting section 12 and the outer peripheral wall of the adapter tube 3. However, the thin-walled bellows 1 has a circular tubular connecting section 12 which is elliptical after processing and has a large difference between the major and minor radii of the ellipse, which can cause difficulties in the socket fitting of the reinforcement sleeve 2. Furthermore, as previously mentioned, the thin-walled nature and the presence of the bellows 11 makes it difficult for the bellows to exert pressure steadily in the axial direction for the transition-fit press fitting of the reinforcement sleeve 2.

To solve this technical problem, the corrugated metal hose based on braze welding in a furnace provided in this embodiment adopts the following assembly steps in step S10: firstly, performing gap assembly on the corrugated pipe connecting section 12 and the reinforcing sleeve 2; after the assembly is in place, the inner diameter of the thin-walled circular tube-shaped connecting section 12 is expanded through an internal expansion process, so that the circular tube-shaped connecting section 12 is tightly matched with the reinforcing sleeve 2. Fig. 10 illustrates a conventional process of increasing the inner diameter of a pipe by axially flaring. In this process, the flaring punch 100 gradually extends into the circular tube-shaped connecting section 12 'along the axial direction of the circular tube-shaped connecting section 12', the inner wall of the circular tube-shaped connecting section 12 'is axially extruded to generate transverse expansion force so as to gradually deform the peripheral wall under gradual stress, and the gradual unbalanced stress causes the problem of flaring cracking of the circular tube-shaped connecting section 12'. For this reason, the present embodiment adopts an internal expansion process of applying only radial pressure to the circular tube-shaped connecting section 12 to integrally and synchronously expand the inner diameter thereof. Specifically, as shown in fig. 11, the inner expansion head first extends into the circular tube-shaped connecting section 12 in a clearance fit manner; after being inserted into place, the inner expansion head expands to apply pressure F11 to the tubular connecting section 12 in the radial direction as a whole to expand the inner diameter thereof simultaneously. Namely, the process synchronously expands the circular tube-shaped connecting section 12 by the same radial pressure F11 at all positions during the expansion, and the uniform stress of the tube wall ensures that the peripheral wall of the circular tube-shaped connecting section 12 is complete and does not crack after the expansion. Compared with the traditional process of expanding the inner diameter of the pipe fitting axially to increase the inner diameter, the radial pressure application adopted by the embodiment is used for integrally and synchronously expanding the inner diameter, so that the expansion process is high in expansion qualification rate, simple in process and high in efficiency.

As shown in fig. 5 and 6, in the present embodiment, the limiting portion 121 is a flared section formed at the port of the circular tube-shaped connecting section 12, so that the flared limiting portion 121 is processed at the port of the circular tube-shaped connecting section 12 while the circular tube-shaped connecting section 12 is expanded in step S10. However, the present invention is not limited to any particular molding process of the stopper portion. In other embodiments, the limiting portion may be machined by an independent step after the inner expanding of the tubular connecting section; or, after the sleeve is sleeved and reinforced, the limit part is processed, and then the inner expansion of the circular tube-shaped connecting section is carried out.

In addition, the shape of the limiting portion is not limited in any way. In other embodiments, the shape of the limiting portion may be a flange 121 formed at the end of the circular tube-shaped connecting section 12, which may be formed during or after the internal expansion of the circular tube-shaped connecting section (as shown in fig. 12). In other embodiments, the limiting portion 121 protruding outwards may be formed on the outer wall of the circular tube-shaped connecting section 12 by protruding radially outwards at the inner wall of the circular tube-shaped connecting section after the inner expansion is completed. The protruding limiting portion 121 may be one or more protruding points (as shown in fig. 13) or a circumferentially continuous protruding ring (as shown in fig. 14 and 15) distributed on the outer peripheral wall of the circular tube-shaped connecting section. The protruding limiting part 121 may be formed on the outer peripheral wall of the circular tube-shaped connecting section 12 near the port thereof (as shown in fig. 13 and 14); the reinforcing sleeve 2 may also be formed in a middle area of the outer peripheral wall of the circular tube-shaped connecting section 12 (as shown in fig. 15), and the reinforcing sleeve 2 is provided with a groove 21 matching with a protruding limiting portion 121, and the limiting portion 121 limits two side walls of the groove 21 in the axial direction of the corrugated tube. Alternatively, in other embodiments, the limiting portion 121 is formed by welding the circular tube-shaped connecting section 12 and the reinforcing sleeve 2 after the internal expansion is completed (as shown in fig. 16); the welding mode can be any one of argon arc welding, laser welding or resistance welding.

After the assembly of the reinforcement sleeve 2 and the processing of the limiting portion 121 are completed, step S30 is performed, and the welded segment 10 is fixed by a tool to press the adapter tube 3 into the welded segment 10. As previously mentioned, the thin wall of the bellows 1 and the provision of the upper bellows portion 11 thereof make it difficult to stably apply pressure in the axial direction for the fitting of the adapter tube 3. Thus, the present embodiment will perform the fixture fixation based on the reinforcement sleeve 2 at the welded section 10. Specifically, the tool can be clamped in the reinforcing sleeve 2 along the radial direction, and the positioning of the reinforcing sleeve 2 and the corrugated pipe 1 is realized through the friction force between the tool and the reinforcing sleeve 2 so that the connecting pipe 3 is pressed into the circular pipe-shaped connecting section 12. Alternatively, the tool may be inserted into the end of the reinforcing sleeve 2 near one end of the corrugated section 11, and the tool is used to position the end of the reinforcing sleeve 2 to press the adapter tube 3 into the circular tube-shaped connecting section 12. Although the tubular connecting section 12 and the reinforcing sleeve 2 are tightly fitted, the axial pressure during the insertion of the adapter tube 3 still causes a relative axial displacement between the tubular connecting section 12 and the reinforcing sleeve 2 (see fig. 8 and 9). At this time, the outer peripheral wall of the limiting portion 121 will block the axial displacement of the reinforcing sleeve 2 relative to the circular tube-shaped connecting section 12 in the direction pointing to the port of the circular tube-shaped connecting section 12, so as to maintain the welded section 10 formed by assembling the two to meet the welded connection of the adapter tube 3.

The assembly of the reinforcement sleeve 2 and the connection piece 3 to one of the tubular connecting sections 12 of the bellows is completed in this way, and the reinforcement sleeve 2 and the connection piece 3 are assembled to the other tubular connecting section 12 of the bellows 1 using the above-described process steps. In the actual assembly process, the assembly of the same components is carried out in the same process step, in particular, after the assembly of the reinforcement sleeve 2 on one of the tubular connecting sections 12 is completed, the reinforcement sleeve 2 is assembled on the other tubular connecting section 12, after which the press fitting of the connecting piece 3 is carried out. However, the invention is not limited in any way thereto. In other embodiments, the reinforcing sleeve and the connecting tube may be assembled on one of the circular tube-shaped connecting sections, and then assembled on the other circular tube-shaped connecting section.

When the corrugated tube 1, the two reinforcing sleeves 2 and the two connection pipes 3 are assembled, step S40 is performed, and solder is placed at the weld between the inner peripheral wall of the circular tube-shaped connecting section 12 and the outer peripheral wall of the connection pipe 3 and at the weld between the outer peripheral wall of the circular tube-shaped connecting section 12 and the inner peripheral wall of the reinforcing sleeve 2. In this embodiment, as shown in fig. 5 and 6, the limiting portion 121 is a flared section formed at the end of the circular tube-shaped connecting section 12, and an inner side accommodating groove 1211 formed between the inner side of the limiting portion 121 and the adapter tube 3 communicates with a weld between the inner peripheral wall of the circular tube-shaped connecting section 12 and the outer peripheral wall of the adapter tube 3; and an outer side accommodating groove 1212 formed between the outer side of the limiting portion 121 and the end portion of the reinforcing sleeve 2 communicates with a weld joint between the outer peripheral wall of the circular tube-shaped connecting section 12 and the inner peripheral wall of the reinforcing sleeve 2. The limiting part 121 isolates the two welding rings in the accommodating grooves at two sides of the limiting part, so that the two welding rings respectively permeate into the corresponding welding seams in a directional manner to ensure the welding quality.

In other embodiments, although the shape of the limiting portion is different from that of the present embodiment, the inner and outer sides thereof may form a receiving groove for receiving solder and isolate the solder. As shown in fig. 12, the limiting portion 121 is a flange section formed at an end of the circular tube-shaped connecting section 12, an inner receiving groove 1211 is formed between an inner surface of the flange section and the adapter tube 3, and an outer receiving groove 1212 is formed between an outer surface of the flange section and an end of the reinforcing sleeve 2. As shown in fig. 14, the limiting portion 12 is a convex ring, an inner side receiving groove 1211 is formed at an inner side groove (inner wall groove corresponding to the convex ring) of the limiting portion 121, and an outer side receiving groove 1212 is formed between an outer side of the limiting portion 121 and an end portion of the reinforcing sleeve 2.

In other embodiments, if the space 121 is not formed with a receiving groove for placing solder, the space 121 shown in fig. 13 is a bump or a solder joint structure shown in fig. 16; at this time, the welding flux at the welding seam between the inner peripheral wall of the circular pipe-shaped connecting section 12 and the outer peripheral wall of the connecting pipe 3 can be placed at the step formed between the end part of the insertion end of the connecting pipe 3 and the inner peripheral wall of the circular pipe-shaped connecting section 12; preferably, a chamfer may be provided at the insertion end portion of the adapter tube 3, which forms an inner groove 1211' with the inner circumferential wall of the circular tube-shaped connecting section 12. The welding flux at the welding seam between the outer peripheral wall of the circular pipe-shaped connecting section 12 and the inner peripheral wall of the reinforcing sleeve 2 can be placed at the step between the end part of the reinforcing sleeve 2 and the outer peripheral wall of the circular pipe-shaped connecting section 12; preferably, a chamfer may be provided at the end of the reinforcement sleeve 2, which chamfer forms an outer groove 1212' with the peripheral wall of the tubular connecting section 12. At this time, the circumferential wall of the circular tube-shaped connecting section 12 isolates the solders in the inner groove 1211 'and the outer groove 1212' to achieve directional penetration of each solder.

And S50, placing the assembly after the solder is placed into a welding furnace to realize the welding of the corrugated pipe 1, the reinforcing sleeve 2 and the connecting pipe 3 in a three-in-one furnace, wherein the equipment adopted in the welding in the furnace can be any one of a mesh belt type tunnel furnace, a vacuum brazing furnace or a gas protection brazing furnace. Besides good welding consistency and clean and bright surface, the brazing in the furnace can effectively eliminate the internal stress of the corrugated pipe during wave control so as to improve the service life of the corrugated pipe under the condition of shock resistance.

The existing metal hose processed by brass flame brazing adopts most of the brazing materials or silver-containing copper-based brazing materials during welding, and the liquidus of the brazing materials is below 900 ℃, so that the melting point of the formed welding seam is relatively low. Taking copper-zinc solder in brass solder as an example, the liquidus line is 890 ℃ and the welding temperature is 905 ℃. When the existing corrugated metal hose is connected with a system pipeline by flame brazing, a low-melting-point welding seam formed during processing on the metal hose is extremely easy to generate secondary welding and melting to cause leakage. While the present embodiment provides a liquidus line of not less than 950 degrees celsius based on brazing material placed in a corrugated metal hose formed by brazing in a furnace. The arrangement greatly improves the heat influence temperature of the welding line when the system pipeline is in welded connection with the connecting pipe 3, thereby effectively avoiding the secondary welding problem of the welding line. Specifically, in this embodiment, the bellows 1, the reinforcing sleeve 2 and the adapter tube 3 are made of stainless steel materials, and during welding, an oxygen-free copper brazing material with a melting point of about 1080 ℃ can be adopted for welding, and the temperature is far higher than the temperature (905 ℃) of flame brazing of the adapter tube 3 and a system pipeline, so that a welding seam formed by the oxygen-free copper brazing material cannot be subjected to heat influence to generate secondary welding, and the performance of the corrugated metal hose and the system pipeline after welding is ensured. In other embodiments, if the adapter tube 3 is a copper tube or a combination of copper and stainless steel tubes, the braze in the furnace may be selected from tin bronze braze with a liquidus above 950 ℃. Also, the temperature is far higher than the temperature of flame brazing of the connecting pipe 3 and the system pipeline, and the welding seam formed by the tin bronze brazing material is not influenced by heat to generate secondary welding.

In this embodiment, the two connection pipes 3 are both connection pipes and are inserted into one end 31 of the corrugated pipe circular pipe shaped connection section 12, and the reduced mouth section 311 is provided with a knurl 310 (as shown in fig. 17A). However, the present invention is not limited in any way thereto. In other embodiments, a wire 310' may be formed on the necked-down section 311 (as shown in FIG. 17B); alternatively, no grooves are formed (as shown in fig. 17C). In other embodiments, the adapter 3 may be a straight tube inserted into one end 31 of the circular tube-shaped connecting section 12 of the bellows without a necking section (as shown in FIG. 17D)

In other embodiments, the adapter 3 may also be a quick-connect type, as shown in fig. 18, where the adapter 3 includes a ball valve connector 3A, a nut 3B, and a ball-end-socket-connector 3C connected to an external system pipe, and the ball valve connector 3A is inserted into the circular-pipe-shaped connecting section 12 near one end 31 of the bellows 1.

Alternatively, the adapter tube 3 may be a flange type as shown in fig. 19 and 19A, and the adapter tube 3 further includes a flange body 3A 'and a flange gasket 3B' connected to an external system pipe.

Still alternatively, the adapter 3 may be of a pipe thread type as shown in fig. 20A or 20B; in fig. 20A, the adapter 3 comprises a ball valve joint 3A, a nut 3B and a ball joint seat 3C 'connected with an external system pipeline, wherein the ball joint seat 3C' is provided with a threaded part 3D for connection; the ball valve joint 3A is inserted into the tubular connecting section 2 near one end 31 of the bellows 1. In fig. 20B, the adapter 3 also has a threaded portion 3D for connecting to an external system pipe. In addition, the connecting pipe can be a straight pipe or an elbow pipe.

The net cover is an important component of the corrugated metal hose, is usually formed by braiding a plurality of metal wires or a plurality of spindle metal bands which are mutually intersected in sequence, is sleeved on the outer surface of the corrugated tube at a specified angle, and plays roles of reinforcing and shielding. The net sleeve not only shares the static load of the corrugated metal hose in the axial direction and the radial direction, but also can ensure the safe and reliable operation of the corrugated metal hose under the condition that the fluid flows along the pipeline to generate pulsation; meanwhile, the corrugated part of the corrugated pipe can be prevented from being directly mechanically damaged in the aspects of relative friction, impact and the like. The strength of the corrugated pipe with the mesh cover woven can be improved by tens of times to tens of times; the highest shielding capacity can reach 99.95%.

Based on the axial and radial static load requirements of the net sleeve during working, the two ends of the net sleeve are required to be fixed during production, and the two ends of the net sleeve in the traditional corrugated metal hose are mainly fixed in a direct closing-up or argon arc welding mode. The simple binding off is fixed its mechanical connection intensity lower and this joint intensity can follow ripple metal collapsible tube's continuous vibration and reduce gradually to lead to the net cover both ends pine to take off, and then seriously shortened ripple metal collapsible tube's life. For argon arc welding type fixing, based on the requirement of argon arc welding on the flatness of a welding position, braided tube wires at the port of a net sleeve are required to be cut before welding so as to be as flush with an outer lining, and then the lining, the net sleeve and an outer sleeve are subjected to three-in-one argon arc welding. The connecting mode has the advantages that the welding time is long, the outer sleeve is required to be polished after argon arc welding is finished to remove the blackening surface, and the problems of low welding efficiency, argon consumption, complex welding procedures and the like exist.

In order to solve the problems of low fixation strength or complex fixation process of the net sleeve in the existing corrugated metal hose, the corrugated metal hose based on brazing in the furnace provided by the embodiment also adopts a brand new net sleeve fixation mode, and the net sleeve fixation mode is high in fixation strength and convenient and fast to process. Specifically, the processing procedure of the corrugated metal hose based on furnace brazing further comprises the following steps:

after the corrugated tube 1, the reinforcing sleeve 2 and the adapter tube 3 are brazed in the furnace, the mesh 4 is sleeved outside the brazed assembly in the furnace (step S60). Specifically, the end portion of the net cover 4 entirely or partially covers the reinforcing sleeve 2 corresponding to the end portion.

Thereafter, the net cover 4 and the reinforcing sleeve 2 will be fixed by means of self-fluxing welding or mechanical connection (step S70). In this step, a circumferential weld of the resistance welding can be formed in the region of the overlap of the wire sleeve 4 and the reinforcement sleeve 2 by means of resistance welding. However, the present invention is not limited in any way thereto. In other embodiments, a plurality of circumferentially distributed weld spots may be formed in the overlap region of the mesh sleeve and the reinforcing sleeve by resistance welding or other self-fluxing welding.

Finally, the outer sleeve 5 is respectively sleeved at two ends of the net sleeve 4, the outer sleeve 5 is in compression joint with the net sleeve 4 in a diameter-reducing manner, and the front end of the outer sleeve 5 is provided with a closing-in step 51 bending towards the direction of the reinforcing sleeve 2 (step S80), as shown in fig. 5. In other embodiments, a closing-in section 51' (as shown in fig. 21) bent toward the direction in which the reinforcing sleeve 2 is located may be formed at the front end of the outer sleeve 5. The front end of the outer sleeve 5 refers to the end of the outer sleeve 5 remote from the corrugated section 11.

The corrugated metal hose medium mesh 4 based on furnace brazing provided in the present embodiment is not furnace brazed with the corrugated tube 1, the reinforcing sleeve 2 and the adapter tube 3. In other words, the net cover 4 is not affected by the brazing material, so that there is no problem of lowering of bending property due to hardening of the brazing material. In addition, the self-fluxing welding or mechanical connection between the net cover 4 and the reinforcing sleeve 2 has realized the basic fixation of both ends of the net cover 4, and the shrinkage press-fitting of the outer sleeve 5 further improves the connection strength of the net cover 4 and also plays a role of coating the end of the net cover 4 to avoid the mesh from being scattered.

In the fixing structure of the net cover 4 provided in this embodiment, the outer sleeve 5 does not need to be welded and does not need to process the front end net wire of the net cover 4 during the fixing connection, so that the fixing strength is high and the processing procedure is simple. Taking DN25 corrugated metal hose based on furnace brazing as an example, the explosion pressure of the net sleeve 4 is up to 24.6Mpa after circumferential welding of the resistance welding is adopted to form a circumferential weld. In the case of a corrugated metal hose based on braze in a furnace, which is welded by resistance welding for local fixation, the burst pressure can reach 20.2Mpa when the number of welding spots reaches sixteen, both of which far exceed the burst pressure of 16.6Mpa required by the standard.

Although the present embodiment is described taking the scheme of shrink-fitting the net cover 4 of the outer sleeve 5 after the self-fluxing welding of the reinforcing sleeve 2 and the net cover 4 as an example. However, the present invention is not limited in any way with respect to the fixation of the net cover. In other embodiments, when the circular tube-shaped connecting section 12, the reinforcing sleeve 2 and the connecting tube 3 are welded in the three-in-one furnace by adopting the structure provided in the embodiment and the circular tube-shaped connecting section 12 is provided with the limiting portion 121, the press-fitting of the mesh sleeve 4 can also be performed by adopting a conventional argon arc welding connection mode (as shown in fig. E) with complicated working procedures, as shown in fig. 22.

Although the invention has been described with reference to the preferred embodiments, it should be understood that the invention is not limited thereto, but rather may be modified and varied by those skilled in the art without departing from the spirit and scope of the invention.

Claims

1. The corrugated metal hose based on braze welding in the furnace is characterized by comprising a corrugated pipe, a reinforcing sleeve, a connecting pipe, a net sleeve sleeved outside the corrugated pipe and an outer sleeve wrapping the end part of the net sleeve; the corrugated pipe comprises a corrugated section in the middle and two circular pipe-shaped connecting sections positioned at two ends of the corrugated section, and each circular pipe-shaped connecting section is provided with a limiting part;

2. The corrugated metal hose based on brazing in a furnace according to claim 1, wherein the corrugated tube connecting section is internally expanded after the reinforcing sleeve is sleeved so that the corrugated tube connecting section and the reinforcing sleeve are tightly fitted.

3. The corrugated metal hose based on brazing in a furnace according to claim 2, wherein a flaring or flanging-like stopper is machined at the port of the circular pipe-shaped connecting section at the same time as or after the completion of the internal expansion;

4. A corrugated metal hose based on braze welding in a furnace according to claim 1 or 3, wherein when the limit portion is in a flared or flanged shape, solder is placed on the inner side and the outer side of the limit portion, respectively, and the solder on the inner side permeates into the weld between the inner peripheral wall of the circular tube-shaped connecting section and the outer peripheral wall of the adapter tube; the welding flux on the outer side permeates into the welding seam between the outer peripheral wall of the circular pipe-shaped connecting section and the inner peripheral wall of the reinforcing sleeve.

5. The furnace braze-based corrugated metal hose of claim 1, wherein the liquidus of the braze material placed is no less than 950 degrees celsius.

6. The furnace braze-based corrugated metal hose of claim 1, wherein the furnace braze-based corrugated metal hose manufacturing method further comprises:

sleeving the net cover outside the brazed assembly in the furnace;

7. The furnace braze-based corrugated metal hose of claim 1, wherein the furnace braze-based corrugated metal hose manufacturing method further comprises:

sleeving the net cover outside the brazed assembly in the furnace;

8. The corrugated metal hose based on brazing in a furnace according to claim 1, wherein a plurality of wire drawing lines or knurls extending in an axial direction are distributed on an outer peripheral wall of one end of the nipple connected to the circular tube-shaped connecting section.

9. The furnace braze-based corrugated metal hose of claim 1, wherein the nipple is any one of a quick-joint type, a tube thread type, a flange type, or a nipple type.

10. The corrugated metal hose based on braze in a furnace of claim 1, wherein the nipple is a copper tube or a stainless steel tube; alternatively, the adapter is an assembly of copper tubing and stainless steel tubing.

11. The corrugated metal hose based on brazing in a furnace according to claim 1, wherein the welding insertion depth L of the nipple with the circular tubular connecting section is as follows: l is more than or equal to 0.2D and less than or equal to 0.7D; wherein D is the outer diameter of the straight section of the upper main body of the connecting pipe.