CN108080806B

CN108080806B - Connecting structure of pipe fitting and connecting part and gas-liquid separator

Info

Publication number: CN108080806B
Application number: CN201611033561.7A
Authority: CN
Inventors: 不公告发明人
Original assignee: Zhejiang Sanhua Intelligent Controls Co Ltd
Current assignee: Zhejiang Sanhua Intelligent Controls Co Ltd
Priority date: 2016-11-21
Filing date: 2016-11-21
Publication date: 2021-01-22
Anticipated expiration: 2036-11-21
Also published as: CN108080806A

Abstract

The invention discloses a connecting structure of a pipe fitting and a connecting part, wherein the connecting part is provided with a through hole connected with the pipe fitting, the edge of the through hole is outwards turned over to form a turned edge, and the pipe fitting is sleeved outside the turned edge; the bushing comprises a barrel body and a flange part extending outwards along the radial direction of the bottom end of the barrel body; the barrel body part and the pipe fitting are fixed through welding, and the turning edge part and the connecting part are fixed through welding; wherein the liner has a linear expansion coefficient less than that of the tubular member. The connecting structure can reduce welding cost and ensure higher welding quality of the pipe fitting and the connecting part. The invention also discloses a gas-liquid separator with the connecting structure.

Description

Connecting structure of pipe fitting and connecting part and gas-liquid separator

Technical Field

The invention relates to the technical field of refrigeration equipment, in particular to a connecting structure of a pipe fitting and a connecting part, and further relates to a gas-liquid separator with the connecting structure.

Background

The gas-liquid separator is generally used in a refrigeration system, and is installed between an evaporator and a compressor. The gas-liquid separator is mainly used for separating gaseous refrigerant and liquid refrigerant, so that the refrigerant enters the compressor from the air suction port of the compressor in a gaseous form, liquid impact on the compressor is prevented, the refrigerant oil returns to the compressor, the compressor is lubricated, normal operation of the compressor is guaranteed, and part of the liquid refrigerant is stored.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a conventional gas-liquid separator.

As shown in the figure, the gas-liquid separator comprises a cylinder body 1 ', two end sockets 2 ' for plugging openings at two ends of the cylinder body 1 ', a connecting pipe 3 ' (comprising an inlet connecting pipe and an outlet connecting pipe) fixedly arranged on one end socket 2 ', and other auxiliary parts. When the whole machine is assembled, the connecting pipe 3' of the gas-liquid separator is welded with a pipeline piece in the system.

Usually, the pipeline in the refrigeration system is a copper pipe, and in order to ensure the welding stability, the connecting pipe 3' of the gas-liquid separator is also made of the copper pipe.

Because the gas-liquid separator needs to have certain pressure bearing performance, the cylinder body 1 ', the end socket 2' and the like are usually manufactured by processing low-carbon steel.

At present, the connecting pipe 3 'and the end socket 2' are connected through brazing, a certain melting depth needs to be ensured during welding, and meanwhile, the leakage phenomenon cannot occur.

Referring to fig. 2-3, fig. 2 is a schematic structural view of the sealing head 2' in fig. 1, and fig. 3 is a partial enlarged view of a portion I in fig. 2.

The end socket 2 ' comprises an arc section 21 ', a platform section 22 ' connected with the arc section 21 ' and a flanging section 23 ' connected with the platform section 22 ', wherein the platform section 22 ' is convenient to locate with the connecting pipe 3 ', and the flanging section 23 ' can ensure the welding penetration of the connecting pipe 3 ' and the end socket 2 '.

Referring to fig. 4-5, fig. 4 is a schematic view of a connection structure between the sealing head 2 'and the connecting pipe 3' in fig. 1; fig. 5 is a partially enlarged view of a portion II in fig. 4.

As shown in the figure, the connecting pipe 3 ' is sleeved outside the flanging section 23 ' of the end socket 2 ', the connecting pipe and the flanging section are fixed by welding, brazing (450 ℃ -950 ℃) is adopted during welding, and silver-based solder is adopted, so that the space between the welding section at the bottom of the connecting pipe 3 ' and the flanging of the end socket 2 ' (namely the area A in the figure) is filled with the silver-based solder by capillary action.

Because the cost of the silver-based solder is high, the copper-based solder is supposed to be adopted for reducing the production cost, but in the actual production process, the welding quality is poor and the leakage rate is high after the copper-based solder is adopted for welding, so that the use requirement of the gas-liquid separator cannot be met.

Other similar pipe fittings and connecting parts have similar problems in practical application, and the production cost and the welding quality cannot be matched.

Therefore, how to improve the connection structure of the pipe and the connecting component to ensure high welding quality while reducing the production cost is a technical problem to be solved by those skilled in the art.

Disclosure of Invention

The invention aims to provide a connecting structure of a pipe fitting and a connecting part, which can ensure higher welding quality of the pipe fitting and the connecting part while reducing welding cost. Another object of the present invention is to provide a gas-liquid separator having the above connection structure.

In order to solve the technical problems, the invention provides a connecting structure of a pipe fitting and a connecting part, wherein the connecting part is provided with a through hole connected with the pipe fitting, the edge of the through hole is outwards turned over to form a flanging, and the pipe fitting is sleeved outside the flanging;

the bushing comprises a barrel body and a flange part extending outwards along the radial direction of the bottom end of the barrel body;

the barrel body part and the pipe fitting are fixed through welding, and the turning edge part and the connecting part are fixed through welding;

wherein the liner has a linear expansion coefficient less than that of the tubular member.

As described above, the present invention provides a connection structure of a pipe and a connection member, in which a bush is additionally provided to be fitted around the pipe, and a linear expansion coefficient of the bush is smaller than that of the pipe; the bushing specifically comprises a barrel part and a turned part extending outwards along the radial direction of the bottom end of the barrel part, namely, the cross section of the bushing is L-shaped; the barrel part of the lining and the pipe fitting are fixed through welding, and the turning edge part and the connecting part are fixed through welding.

Compared with the prior art, the welding area of the connecting structure when the pipe fitting is connected with the connecting part is converted between the flanging of the pipe fitting and the connecting part into the space between the cylinder body part of the pipe fitting and the cylinder body part of the lining and the space between the flanging part of the lining and the connecting part, because the linear expansion coefficient of the lining is smaller than that of the pipe fitting, in the welding process, the gap between the cylinder body part and the pipe fitting can be reduced, the capillary action of the welding flux can be enhanced, the welding flux can be fully distributed in the gap, meanwhile, the gap between the flanging part and the connecting part is generally in the vertical direction, the influence of thermal expansion factors in the welding process is small, the welding quality is easy to guarantee, and therefore, the connecting structure has low requirement on the welding flux, and the welding flux with low cost can be selected while.

The welding part of the connecting part and the turning part is a plane structure parallel to the turning part.

The pipe fitting has a linear expansion coefficient larger than that of the connecting member.

The invention also provides a gas-liquid separator which comprises a cylinder, end sockets for plugging openings at two ends of the cylinder, and connecting pipes fixedly connected to the end sockets, wherein the connecting pipes are communicated with the inner cavity of the cylinder; the connecting pipe is connected with the end socket through the connecting structure, the connecting pipe is the pipe fitting, and the end socket is the connecting part.

The end socket and the connecting pipe of the gas-liquid separator are connected by adopting the connecting structure, so that the gas-liquid separator also has corresponding technical effects, and the discussion is not repeated.

The connecting pipe is specifically a copper pipe, and the lining is specifically a lining made of low-carbon steel.

The barrel part of the bush is fixed with the connecting pipe through high-temperature brazing, and the edge turning part of the bush is fixed with the end enclosure through high-temperature brazing.

The brazing welding flux of the barrel body part and the connecting pipe is copper-based, and the brazing welding flux of the turning edge part and the sealing head is also copper-based.

The clearance between the barrel body part and the connecting pipe is 0.02-0.05 mm.

The height of the barrel part of the bushing is 2-6 mm, and the radial size of the turning part of the bushing is 2-6 mm.

The diameter of the connecting pipe is more than 16 mm.

Drawings

FIG. 1 is a schematic view of a conventional gas-liquid separator;

FIG. 2 is a schematic structural view of the head of FIG. 1;

FIG. 3 is a partial enlarged view of portion I of FIG. 2;

FIG. 4 is a schematic view of a connection structure of the sealing head and the connecting pipe in FIG. 1;

FIG. 5 is a partial enlarged view of the portion II in FIG. 4;

FIG. 6 is a schematic view of a connection structure of a connection pipe and a head of a gas-liquid separator in a specific embodiment;

FIG. 7 is a partial enlarged view of the portion III in FIG. 6;

FIG. 8 is a cross-sectional view of the bushing of FIG. 6;

fig. 9 is a top view of the bushing shown in fig. 8.

Wherein, the one-to-one correspondence between component names and reference numbers in fig. 1-5 is as follows: the device comprises a cylinder body 1 ', a seal head 2', a circular arc section 21 ', a platform section 22', a flanging section 23 'and a connecting pipe 3';

wherein, the one-to-one correspondence between component names and reference numbers in fig. 6-9 is as follows: the sealing head 20, the flanging 23, the connecting pipe 30, the bushing 40, the barrel part 41 and the flanging part 42.

Detailed Description

Aiming at the technical problems that when the end socket similar to a gas-liquid separator is connected with the connecting pipe in the prior art, the welding quality of the welding part is poor or the cost is high, a great deal of research work is carried out, and the reason that after copper-based solder is adopted, the welding quality between the end socket and the connecting pipe is reduced is found to be that: the linear expansion coefficient of the connecting pipe made of copper is larger than that of the end socket made of steel, and when welding is performed, due to the effect of high temperature, the gap of the area A between the connecting pipe and the flanging section of the end socket is enlarged.

Wherein, the gap variation of the a region can be calculated by the following formula:

△J＝D×(T1-T2)×(α2-α1) (1)

in the formula (1), Δ J is a gap variation, D is a diameter of the connecting pipe, T1 is a welding temperature, T2 is a room temperature, α 2 is a linear expansion coefficient of the connecting pipe, and α 1 is a linear expansion coefficient of the end socket.

As can be seen from the above formula (1), the gap in the region a becomes larger as the temperature is higher, and the capillary action after the solder is melted is weakened by the larger gap during the soldering process, resulting in the occurrence of soldering defects such as blowholes and solder breakage. After the copper-based solder is adopted, the reason for the reduction of the welding quality is that when the copper-based solder is adopted for welding, the enlargement amount of the gap is larger than the maximum value of the reasonable gap, so that the capillary action of the solder is reduced, the gap is difficult to be fully distributed by the solder, the bad phenomena of air holes, welding breakage and the like are caused, the product has higher leakage rate, and therefore, in order to ensure the quality of the product, the silver-based solder with higher cost has to be adopted, and the production cost and the product quality cannot be balanced.

On the basis of the above findings, the present invention provides a solution to the above technical problems, and the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.

Without loss of generality, the connection structure of the pipe and the connection member described in the present embodiment is explained mainly with the connection structure of the connection pipe and the head of the gas-liquid separator as a main body. It will be understood that other similar pipe and connecting member connection arrangements are similar to this principle and will not be repeated.

Referring to fig. 6 to 7, fig. 6 is a schematic view illustrating a connection structure between a connection pipe and a head of a gas-liquid separator according to the present embodiment, and fig. 7 is a partially enlarged view of a portion III in fig. 6.

In this embodiment, the end socket 20 of the gas-liquid separator has a through hole connected with the connecting pipe 30, so that the connecting pipe 30 can be connected with the inner cavity of the cylinder of the gas-liquid separator, wherein the edge of the through hole of the end socket 20 is turned outwards to form a flange 23; when the two are connected, the connecting pipe 30 is sleeved outside the flange 23, and the flange 23 can play a role in positioning the connecting pipe 30.

Referring also to fig. 8-9, fig. 8 is a schematic view of the bushing of fig. 6; fig. 9 is a top view of the bushing shown in fig. 8.

The connecting structure further comprises a bushing 40, wherein the bushing 40 comprises a barrel part 41 and a flange part 42 which extends outwards along the bottom end of the barrel part in the radial direction, namely, the cross section of the bushing 40 is in an L-shaped structure.

Specifically, the bushing 40 is sleeved on the bottom of the adapter tube 30, which is the end of the adapter tube 30 close to the end socket 20, the cylindrical body 41 is fixed to the adapter tube 30 by welding, and the flange 42 is fixed to the end socket 20 by welding, so as to connect the adapter tube 30 and the end socket 20.

In addition, the liner 40 has a linear expansion coefficient smaller than that of the nipple 30.

In the specific scheme, in order to ensure the pressure bearing of the gas-liquid separator and the requirement of connection with a system pipeline, the connecting pipe 30 is made of a copper pipe, the end socket 20 is made of a low-carbon steel material, and the lining 40 can also be made of a low-carbon steel material.

As described above, compared to the conventional connection of the adapter tube and the end socket, the present embodiment employs the above structure to convert the welding region between the adapter tube and the end socket, i.e., region a shown in fig. 5, into region B between the adapter tube 30 and the cylindrical body 41 of the bushing 40 and region C between the turned edge portion 42 of the bushing 40 and the end socket 20, as shown in fig. 7.

For the B region where the linear expansion coefficient of the bush 40 is smaller than that of the adapter tube 30, when the bush 40 is mounted on the outer side of the adapter tube 30, the gap variation Δ J can be determined to be negative according to the aforementioned formula (1), that is, the gap of the B region is decreased with the increase of the soldering temperature during soldering, so that the capillary action of the B region is enhanced during soldering, and the solder can sufficiently fill the gap.

For the area C, the clearance between the turned part 42 of the lining 40 and the seal head 20 is in the vertical direction generally, and the influence of thermal expansion factors in the welding process is small, so the welding quality of the area C is easy to guarantee, and the requirement on welding flux is low.

As can be seen, after the bushing 40 is provided, as long as the welding quality of the B region can be ensured, the welding quality between the adapter tube 30 and the header 20 can be ensured. As analyzed above, since the gap in the B region is reduced during the soldering process, the requirement for the solder is low, so that in the actual setting, the solder with low cost can be selected to replace the existing silver-based solder while the soldering quality is ensured, thereby reducing the production cost.

It should be noted that, as described above, if the connecting pipe 30 is fitted inside the flange 23 of the end socket 20, the flange 23 of the end socket 20 is located outside, and the linear expansion coefficient of the end socket 20 is smaller than that of the connecting pipe 30, so that the gap between the connecting pipe 30 and the flange 23 is also reduced during welding, but tests have found that solder easily falls into the cylinder of the gas-liquid separator during welding and still affects the quality of the gas-liquid separator, and therefore the above-described connection method using the bush 40 is preferable.

In a specific scheme, high-temperature brazing is adopted for welding the barrel body 41 and the connecting pipe 30 and welding the turnup portion 42 and the end enclosure 20, wherein the high-temperature brazing refers to brazing with the welding temperature of above 950 ℃.

More specifically, the brazing solder of the barrel 41 and the adapter tube 30 is copper-based, and the brazing solder of the flange 42 and the end socket 20 is also copper-based.

In order to further ensure the stability of the welding quality, on the basis of selecting the copper-based solder, the gap value between the cylinder part 41 and the connecting pipe 30 is set to be 0.02-0.05 mm.

Furthermore, the welding part of the end socket 20 and the turned part 42 of the bushing 40 is a plane structure parallel to the turned part 42, so that the clearance between the end socket 20 and the turned part 42, namely the C area, can be completely free from the influence of thermal expansion factors in the vertical direction, and the clearance in the C area can be kept in the reasonable clearance range of the copper-based solder in the welding process, thereby ensuring the stability of the welding quality.

It should be understood that besides the above-mentioned copper-based solder, other solders with lower cost can be selected in practice, and the gap value of the B region can be adjusted reasonably according to the selection of the solders to ensure the welding quality.

As above, after the bushing 40 structure is provided, as long as the welding tightness of the B region and the C region can be ensured during welding, the tightness between the connection pipe 30 and the end enclosure 20 can be ensured, and at this time, the welding quality between the connection pipe 30 and the flange 23 of the end enclosure 20 may not be required, that is, it may not be necessary to weld the connection pipe 30 and the flange 23 of the end enclosure 20.

In a specific scheme, the height of the cylinder body part 41 of the lining 40 can be selected within the range of 2-6 mm, and the radial size of the turning part 42 of the lining 40 can be selected within the range of 2-6 mm, so that a certain welding area is ensured, and the welding quality is ensured.

In addition, according to the calculation of the formula (1), when the pipe diameter of the connecting pipe 30 reaches a certain value or more, if the existing connection structure is adopted, the requirement for the solder is more strict in order to ensure the welding quality between the connecting pipe 30 and the end socket 20, so in practice, when the pipe diameter of the connecting pipe 30 is more than 16mm, the structure provided by the scheme is preferably adopted to realize the connection between the connecting pipe 30 and the end socket 20.

Besides the connecting structure of the pipe fitting and the connecting part, the invention also provides a gas-liquid separator, which comprises a cylinder body, end sockets 20 for plugging openings at two ends of the cylinder body, and a connecting pipe 30 fixedly connected to the end sockets 20, wherein the connecting pipe 30 is communicated with the inner cavity of the cylinder body; wherein, the end socket 20 and the connecting pipe 30 are connected by adopting the connecting structure.

Other structures of the gas-liquid separator can be found in the prior art, and are not described in detail herein.

The connection structure of the pipe and the connection member and the gas-liquid separator provided by the present invention are described in detail above. The principles and embodiments of the present invention are explained herein using specific examples, which are presented only to assist in understanding the method and its core concepts. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention.

Claims

1. The connecting structure comprises a pipe fitting and a connecting part, wherein the connecting part is provided with a through hole connected with the pipe fitting, the edge of the through hole is outwards turned over to form a turned edge, and the pipe fitting is sleeved outside the turned edge; the method is characterized in that:

the bushing (40) is sleeved at the bottom of the pipe fitting and comprises a barrel body part (41) and a flange part (42) extending outwards along the radial direction of the bottom end of the barrel body part (41);

the barrel part (41) and the pipe fitting are fixed through welding, and the turned edge part (42) and the connecting part are fixed through welding; the pipe is positioned between the barrel part (41) and the flanging;

wherein the liner (40) has a linear expansion coefficient less than that of the tubular member.

2. The pipe fitting and connecting member connection structure according to claim 1, wherein a portion where the connecting member is welded to the turned-over portion is a planar structure parallel to the turned-over portion (42).

3. The pipe fitting and connecting member connection structure according to claim 1 or 2, wherein a coefficient of linear expansion of the pipe fitting is larger than a coefficient of linear expansion of the connecting member.

4. The gas-liquid separator comprises a cylinder body, end sockets (20) for plugging openings at two ends of the cylinder body, and connecting pipes (30) fixedly connected to the end sockets (20), wherein the connecting pipes (30) are communicated with an inner cavity of the cylinder body; characterized in that the connecting pipe is connected with the end socket through the connecting structure of any one of claims 1 to 3, the connecting pipe (30) is the pipe fitting, and the end socket (20) is the connecting part.

5. Gas-liquid separator according to claim 4, characterized in that the adapter tube (30) is embodied as a copper tube and the bushing (40) is embodied as a bushing made of mild steel.

6. The gas-liquid separator according to claim 4, wherein the barrel portion (41) of the bushing (40) and the adapter tube (30) are fixed by high temperature brazing, and the turned-over portion (42) of the bushing (40) and the head (20) are also fixed by high temperature brazing.

7. The gas-liquid separator according to claim 6, wherein the brazing solder of the barrel portion (41) and the adapter tube (30) is copper-based, and the brazing solder of the turned-over portion (42) and the end socket (20) is also copper-based.

8. The gas-liquid separator according to claim 7, wherein a clearance between the cylindrical body portion (41) and the joint pipe (30) is 0.02 to 0.05 mm.

9. The gas-liquid separator according to any one of claims 4 to 8, wherein the height of the cylindrical body portion (41) of the liner (40) is 2 to 6mm, and the radial dimension of the turn-up portion (42) of the liner (40) is 2 to 6 mm.

10. The gas-liquid separator according to any one of claims 4-8, wherein the adapter tube (30) has a diameter of 16mm or more.