CN210266379U

CN210266379U - Pipe fitting connection structure, silencer, air conditioning system and refrigerating system

Info

Publication number: CN210266379U
Application number: CN201821452614.3U
Authority: CN
Inventors: 不公告发明人
Original assignee: Xinchang Sitong Electromechanical Co ltd
Current assignee: Xinchang Sitong Electromechanical Co ltd
Priority date: 2018-09-05
Filing date: 2018-09-05
Publication date: 2020-04-07
Anticipated expiration: 2028-09-05

Abstract

The utility model relates to a pipe fitting connection structure, a muffler, an air conditioning system and refrigerating system, wherein pipe fitting connection structure includes body and sleeve through welded fastening setting, and the body is made by stainless steel material, and the sleeve is made by copper material, the sleeve has the portion of turning up, the body includes tubulose portion, tubulose portion be used for with the sleeve cooperation is connected, the barrel at least most is located in the tubulose portion, the portion of turning up is the approximate annular structure, the portion of turning up is located the body outside, the wall thickness more than or equal to of telescopic portion of turning up the wall thickness of body perhaps the wall thickness more than or equal to of telescopic portion of turning up the body the wall thickness of tubulose portion. After the wall thickness of the eversion part of the copper sleeve is increased, heat transfer can be relatively good when a connecting pipe such as a copper pipe for subsequent connection with a system is welded, and therefore the subsequent welding and assembling of the pipe connecting structure are facilitated.

Description

Pipe fitting connection structure, silencer, air conditioning system and refrigerating system

Technical Field

The utility model belongs to the technical field of the refrigeration.

Background

Products in the refrigeration technology field include air conditioners, refrigerators, freezers and the like, generally, copper pipes are used as connecting pipes to connect two parts of the systems, and in order to be conveniently connected with the copper pipes, a plurality of parts are correspondingly made of copper materials. For example, the basic components of refrigeration systems such as liquid reservoirs, silencers, four-way valves, solenoid valves, compressors, etc., and the connecting pipe fittings are usually made of copper pipes, but at present, the components may be made of different materials, for example, stainless steel materials, etc., and the connecting problem between two different materials may be used in the system.

Because stainless steel has a low heat conduction system, the problem of improving heat conduction needs to be considered when welding.

SUMMERY OF THE UTILITY MODEL

The utility model provides a pipe fitting connection structure, pipe fitting connection structure make things convenient for and copper union coupling, and pipe fitting connection structure is when welding in the back through stove after the equipment, and welding process is more reliable, provides following technical scheme for this reason:

a pipe connecting structure comprises a body and a sleeve, wherein the body and the sleeve are fixedly arranged by welding, the body is made of stainless steel material, the sleeve is made of copper material and comprises a barrel body part and an eversion part, the body portion being substantially hollow cylindrical, the body including at least one connection port portion, the body including a tubular portion at the port portion, the tubular part is used for being matched and connected with the sleeve, the barrel part is at least mostly positioned in the tubular part, the barrel body part and the outward turning part are of an integral structure, the outward turning part is formed by outward turning or bending the barrel body part, the everting portion is located relatively outside the body, the everting portion is of a substantially ring-shaped configuration, and the wall thickness (D) of the everting portion of the sleeve is greater than or equal to the wall thickness (t0) of the body or the wall thickness (D) of the everting portion of the sleeve (10) is greater than or equal to the wall thickness (t) of the tubular portion of the body.

The body can comprise a base pipe and a variable-diameter part, the tubular part is formed by spinning and necking, the variable-diameter part is positioned between the base pipe and the tubular part, the base pipe, the variable-diameter part and the tubular part are of an integral structure, and the outer diameter (d1) of the base pipe is more than twice of the outer diameter (d2) of the tubular part; the wall thickness of the body (t0) refers to the wall thickness of the base pipe.

A step part is arranged on the inner wall part of the tubular part matched with the barrel part at the port part of the body, an axial distance is reserved between the end part of the sleeve relatively close to the step part and the step part, an annular space for placing a welding ring is formed between the step part and the end part of the sleeve, and the annular space is used for placing the welding ring when the body and the sleeve are welded; the barrel part of the sleeve comprises a plurality of protruding parts, and the protruding parts form a structure of local clearance and local interference between the outer wall of the barrel part and the inner wall part of the body; the protruding portion comprises a plurality of strip-shaped protrusions, the length of each strip-shaped protrusion is smaller than the length (L) of the barrel body portion matched with the inner wall portion, or the length of each strip-shaped protrusion is smaller than the length (L) of the inner wall portion matched with the barrel body portion, and a certain axial distance is reserved between the two sides of each strip-shaped protrusion and the matching position.

A step part is arranged on the inner wall part of the tubular part matched with the barrel part at the port part of the body, an axial distance is reserved between the end part of the sleeve relatively close to the step part and the step part, an annular space for placing a welding ring is formed between the step part and the end part of the sleeve, and the annular space is used for placing the welding ring when the body and the sleeve are welded; the barrel part of the sleeve comprises a plurality of protruding parts, and the protruding parts form a structure of local clearance and local interference between the outer wall of the barrel part and the inner wall part of the body;

the sleeve can further comprise an inward-turning part, the inward-turning part is positioned at one end, close to the inside, of the sleeve, the inward-turning part is formed by inward flanging or bending of the barrel body part, the inward-turning part and the barrel body part form a positioning step part, and the barrel body part, the outward-turning part and the inward-turning part are of an integral structure; the sleeve is relatively close to the end part of the step part of the body, the sleeve further comprises a guide part, an axial distance is reserved between the guide part and the step part, an accommodating part is formed between the step part and the guide part, and the accommodating part is used for placing a welding ring when the body and the sleeve are welded.

Simultaneously, this technical scheme still provides muffler, air conditioning system and refrigerating system who has above-mentioned pipe fitting connection structure. The outward turning part is arranged at the part, used for being matched with the end part of the stainless steel pipe body, of the copper sleeve, the wall thickness of the outward turning part of the sleeve is increased, the wall thickness of the outward turning part of the sleeve is larger than or equal to that of the stainless steel body, and the heat conductivity coefficient of copper is far larger than that of stainless steel. After the wall thickness of the eversion part of the copper sleeve is increased, heat transfer can be relatively good when a connecting pipe such as a copper pipe for subsequent connection with a system is welded, and therefore the subsequent welding and assembling of the pipe connecting structure are facilitated.

Drawings

FIG. 1: the utility model provides a structural schematic diagram of a pipe fitting connecting structure, in particular to a structural schematic diagram of a pipe fitting connecting structure used for a silencer;

FIG. 2: fig. 1 is a partially enlarged schematic view of a portion a of the pipe connecting structure;

FIG. 3 is a schematic view of one embodiment of the sleeve shown in FIGS. 1 and 2;

FIG. 4: fig. 1, 2 show a schematic view of another embodiment of a sleeve;

FIG. 5: a schematic representation of an application state of the tubular connection;

FIG. 6: a schematic view of one state of an assembly process of another embodiment of a pipe fitting connection structure.

The symbols in the drawings illustrate that:

10-a sleeve;

11-a barrel portion, 111-an outer wall portion;

12-eversion; 13. 13' -protrusion

14-a guide; 15-an inverted portion;

20. 20 a-a body;

21-port section, 22-step section; 211-an annular space; 212-a weld ring; 23-end portion; 24-

A tubular part, 25-base pipe, 26-diameter-changing part;

30-connection pipe.

Detailed Description

The following describes the technical solution with reference to specific examples.

The pipe fitting connecting structure of the technical scheme can be used for a silencer, a liquid storage device, a separator and other stainless steel bodies and needs to be used for the occasions connected with copper pipes, and the pipe fitting connecting structure can be used for the products, can be used for one end of the products and comprises stainless steel and a copper sleeve, and can also be used for both ends. Referring to fig. 1 to 5, fig. 1 is a schematic view of a structure of a muffler (details of the inside are not shown), fig. 2 is a schematic view of a portion a shown in fig. 1, fig. 3 is a schematic view of an embodiment of a sleeve of the structure shown in fig. 2, fig. 4 is a schematic view of another embodiment of the sleeve, and fig. 5 is a schematic view of a partial structure of the pipe connection structure in a use state.

As shown in the figures, the silencer comprises a body 20 and two sleeves 10, the body 20 is formed by spinning stainless steel pipes, the body comprises a base pipe 25, a variable-diameter portion 26 and a tubular portion 24, the variable-diameter portion 26 is located between the base pipe 25 and the tubular portion 24 or the variable-diameter portion 26 connects the base pipe 25 and the tubular portion 24, the base pipe, the variable-diameter portion and the tubular portion are of an integral structure, the outer diameter (d1) of the base pipe is more than twice of the outer diameter (d2) of the tubular portion 24, even the outer diameter (d1) of the base pipe can be more than 2.5 times of the outer diameter (d2) of the tubular portion 24; the wall thicknesses of the base pipe, the diameter-variable portion, and the tubular portion may be different due to the spinning process. The connection port part 21 for fluid inflow and fluid outflow is formed at two ends of the body 20 through spinning necking, the port part 21 is smaller than a base pipe 25 of the body 20, a step part 22 can be arranged at the inner wall part of the port part 21 of the body 20, the body 20 further comprises a tubular part 24 which is matched and connected with the sleeve 10 at the port part 21, and at least one end of the body in the port parts at two sides is provided with the tubular part 24 which is matched and connected with the sleeve 10. It should be noted here that the tubular portion 24 may be a part of the port portion 21, or the port portion 21 may be a part of the tubular portion 24, or both the tubular portion 24 and the port portion 21 may or may not be partially overlapped.

The sleeve 10 for connection made of copper pipes comprises an outward turning part 12 and a generally hollow cylindrical body part 11, wherein the outward turning part 12 is positioned at the opposite outer side of a body 20, the body part 11 is matched with the tubular part 24, the body part 11 is basically positioned in the tubular part 24 of the body or at least most of the body part 11 is positioned in the tubular part 24 of the body, the sleeve 10 of the embodiment also comprises an inward turning part 15, the inward turning part 15 is formed by inward flanging or bending or flanging or bending the barrel part 11 at the opposite inner end of the sleeve 10, the flanging or bending in the specification comprises direct flanging or bending processing or flanging or bending processing and then machining, the inward turning part 15 and the barrel part 11 form a positioning step part, the positioning step part can be used for positioning when a silencer is welded with a connecting copper pipe later, the outward turning part 12 is formed by outward flanging or bending the barrel part 11 at the opposite outer end of the sleeve 10, here again including being flanged or bent outwardly and machined, the out-turned portion 12 is of generally annular configuration and is disposed projecting from the body portion 11. The sleeve 10 further includes a guide portion 14, and the barrel portion 11, the outward turned portion 12, and the inward turned portion 15 of the present embodiment are integrally formed. The evagination portion 12 is formed by flanging or bending the barrel portion 11, the barrel portion 11 and the evagination portion are of an integral structure, the body includes at least one connecting port 21, the body 20 includes a tubular portion 24 at the port 21, the tubular portion 24 is used for matching connection with the sleeve 10, the barrel portion 11 is at least mostly located in the tubular portion 24 or even basically located in the tubular portion, the evagination portion is of a ring-shaped structure, the wall thickness (D) of the evagination portion of the sleeve 10 is relatively increased, such as the wall thickness (D) of the evagination portion of the sleeve 10 is greater than or equal to the wall thickness (t0) of the body, or the wall thickness (D) of the evagination portion of the sleeve 10 is greater than or equal to the wall thickness (t) of the tubular portion of the body, thus, when the wall thickness of the evagination portion is relatively greater, the muffler is connected with a system, the heat conducting property can be improved, and the subsequent welding with a system is facilitated. Specifically, the wall thickness (D) of the eversion part can be set to be more than 0.5mm, or the wall thickness (D) of the eversion part can be set to be more than 1mm, or more than 1.2mm, even about 1.5mm or even 2mm or even 2.5mm when necessary, and the wall thickness (D) can be specifically set according to the pipe diameter and the system requirement; and the wall thickness of the body (t0) is typically 0.5mm, 1mm, 2mm, 0.8mm, 1.5mm, 1.2mm, etc.

A step part 22 is arranged on the inner wall part of the tubular part matched with the barrel part 11 at the port part of the body, the end part of the sleeve relatively close to the step part 22 has an axial distance with the step part, an annular space 211 for placing a welding ring is formed between the step part and the end part of the sleeve, the annular space can be used for placing the welding ring when the body and the sleeve are welded, and the annular space is slightly larger than the welding ring; the barrel of the sleeve may further comprise a plurality of protrusions, which form a structure of local clearance and local interference between the outer wall of the barrel 11 and the inner wall of the body; the protruding portion 13 may be a plurality of strip-shaped protrusions, the length of the strip-shaped protrusions is less than the length (L) of the barrel portion 11, which is matched with the inner wall portion, or the length of the strip-shaped protrusions is less than the length (L) of the inner wall portion, which is matched with the barrel portion 11, and both sides of the strip-shaped protrusions have a certain axial distance from the matching position. The protrusion 13' may be a plurality of protrusions or dots.

Due to the arrangement of the protruding part, when the sleeve 10 is pressed into the connecting port part 21 of the body 20, the outer wall part of the barrel part 11 and the inner wall part of the tubular part 24 at the port part 21 of the body 20 can form a matching relation of local interference and local clearance, so that the primary fixing mode between the sleeve 10 and the body is relatively stable, the sleeve cannot fall off in the conveying process, and meanwhile, the sleeve can be directly placed into a furnace for brazing, such as a welding furnace, such as a tunnel furnace without other fixing tools, so that the process cost is reduced. The inner wall part and the outer wall part are partially in interference fit, and then are partially abutted. The eversion 12 may likewise form a substantially compressed or partially compressed, partially gapped fit with the end 23 of the body.

An annular space 211 is formed between the step 22 of the body 20 and the inside-turned part 15 of the sleeve 10, a certain distance is formed between the end of the sleeve relatively close to the step 22 and the step 22 in the axial direction, and an annular space for placing a welding ring is formed between the step 22 and the end of the sleeve for arranging the welding ring for welding, so that the welding ring can be melted and filled in a gap part between the outer wall part 111 of the cylinder part 11 and the inner wall part of the body 20 after passing through a tunnel furnace, for example, by welding in a furnace to form a solder filling part, and also can be filled in a gap part between the outside-turned part 12 and the end 23 of the body. The outer wall of the cylindrical body 11 and the inner wall of the tubular part 24 of the body 20 are partially in interference with each other or partially in clearance, so that the cylindrical body 11 and the tubular part 24 can be fixed in position in the radial direction and the axial direction after assembly. Since the protrusion is configured to form a local interference or a local gap between two mating surfaces by causing the local interference between the two mating surfaces, the structure and shape of the protrusion are not limited in this specification as long as the object is achieved. The protrusion may be provided on the inner wall of the tubular portion of the body, so that the outer wall 111 of the body 11 and the inner wall 240 of the tubular portion 24 of the port 21 of the body 20 are engaged with each other with a local interference or a local gap.

The sleeve further comprises an inward-turning part 15, the inward-turning part 15 is located at one end, close to the inside, of the sleeve, the inward-turning part 15 is formed by inward flanging or bending of the barrel part 111, the inward-turning part and the barrel part form a positioning step part, and the barrel part, the outward-turning part and the inward-turning part are of an integral structure; the sleeve further comprises a guide part 14 at the end part relatively close to the step part 22 of the body, a certain distance is formed between the guide part and the step part in the axial direction, and an annular space for accommodating a welding ring is formed between the step part and the guide part and used for placing the welding ring used when the body and the sleeve are welded. The guide part is provided with and does benefit to the more convenient assembly of sleeve and body, in addition when the equipment, can place the welding ring in the port portion position of body to when pressing in through the sleeve, utilize the guide part area to weld the annular space that the ring impresses together, weld the ring and press close to guide part 14 relatively like this, set up like this, when can making body and sleeve welding, the clearance position between the outer wall portion that welds the ring melting is favorable to filling to barrel 11 and the inner wall portion of body 20 together.

The above description is given by way of example of a silencer, and the above technical solution can be applied to other products such as liquid reservoirs or separators, and will not be repeated here.

The pipe connection structure can be used for an air conditioning system, the air conditioning system comprises a first component, the first component comprises the pipe connection structure, the first component comprises a body made of stainless steel materials and a sleeve made of copper materials, one end of the sleeve is connected with the body in a welding mode through a furnace, the air conditioning system further comprises a copper pipe 30 connected with the sleeve, please refer to fig. 5, the sleeve 10 is connected with the copper pipe 30 in a welding mode, such as flame brazing, and the melting temperature of a welding material used for welding the sleeve 10 of the pipe connection structure with the copper pipe is lower than that of the welding material used for welding the sleeve with the body made of the stainless steel. Because stainless steel has relatively poor heat conduction and copper has good heat conduction, after the wall thickness of the outward turning part of the sleeve is increased, the heat conduction effect of welding the sleeve 10 and the copper pipe 30 can be improved, and the welding efficiency and the welding quality are improved.

Similarly, the tube connection structure can be used in a refrigeration system comprising a first component comprising the tube connection structure as described above or the first component comprising a body of stainless steel material and a sleeve of copper material as described above, the body of stainless steel material and the sleeve of copper material being connected as described above, one end of the sleeve of the tube connection structure being welded to the body by furnace welding, such as tunnel furnace welding, the refrigeration system further comprising a copper tube connected to the sleeve, the sleeve being welded to the copper tube, such as flame brazing welding, the melting temperature of the solder used for welding the sleeve of the tube connection structure to the copper tube being lower than the melting temperature of the solder used for welding the sleeve to the stainless steel.

Specifically, the melting temperature of the solder used for welding the sleeve and the copper pipe of the pipe fitting connection structure can be approximately 850 ℃ +/-50 ℃, and is lower than the melting temperature of the solder used for welding the sleeve and the stainless steel, and is approximately 1000 ℃ or 1030 ℃, so that the subsequent welding temperature is lower than the original welding temperature, the original welding part is not affected, namely, the connection between the stainless steel and the copper pipe is conveniently realized, and the selection of the system on parts is more convenient.

A second embodiment of the pipe connection structure will be described, and fig. 6 is a partial structural view of the stainless steel body and the copper sleeve of the second pipe connection structure after assembly and before welding. The pipe fitting connecting structure comprises a body 20a and a sleeve 10, wherein the body 20a is formed by processing stainless steel pipes, the difference between the body 20a and the above embodiment is that the body is not processed by spinning, the inner wall part of the port part of the body is not provided with a step part, a welding ring 212 is guided to be pressed in through a guide part when the sleeve is pressed in, the outer diameter of the welding ring 212 in a free state is larger than the inner diameter of the inner wall part of the body, when the pipe fitting connecting structure is assembled, the welding ring 212 is firstly put into the port part of the body, the welding ring and the port part are in elastic fit, then the sleeve is put in, and when the sleeve is pressed in, the sleeve. Likewise, the wall thickness D of the eversion 12 is greater than the wall thickness t of the body 20a, others can refer to the above embodiments.

The above embodiments are only exemplified to better illustrate the related technical solutions, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting, for those skilled in the art, without departing from the technical principles, several improvements and modifications can be made, such as mutual combination, modification or equivalent replacement, without departing from the spirit and scope of the present invention, and all such improvements and modifications should be considered as the protection scope of the present invention.

Claims

1. A pipe connecting structure comprising a body (20) and a sleeve (10), the body (20) and the sleeve (10) being fixedly arranged by welding, the body being made of stainless steel material, the sleeve being made of copper material, the sleeve (10) comprising a barrel portion (11) and an eversion portion (12), the barrel portion (11) being substantially hollow and cylindrical, the body comprising at least one connecting port portion (21), the body (20) comprising a tubular portion (24) at the port portion (21), the tubular portion (24) being adapted to be fittingly connected to the sleeve (10), the barrel portion (11) being at least mostly located within the tubular portion (24), characterized in that the barrel portion (11) and the eversion portion are of one-piece construction, the eversion portion being formed by flanging or bending the barrel portion (11), the eversion portion (12) being located relatively outside the body, the eversion is substantially ring-shaped, the wall thickness (D) of the eversion of the sleeve (10) being equal to or greater than the wall thickness (t0) of the body or the wall thickness (D) of the eversion of the sleeve (10) being equal to or greater than the wall thickness (t) of the tubular part of the body.

2. The tubular connection structure of claim 1, wherein the body comprises a base pipe and a variable diameter portion, the tubular portion is formed by spinning and necking, the variable diameter portion (26) is located between the base pipe (25) and the tubular portion, the base pipe, the variable diameter portion and the tubular portion are of an integral structure, and an outer diameter (d1) of the base pipe is more than twice an outer diameter (d2) of the tubular portion (24); the wall thickness of the body (t0) refers to the wall thickness of the base pipe.

3. A pipe connecting structure according to claim 1 or 2, wherein said body is provided with a step (22) at said port portion at an inner wall portion of said tubular portion fitted to said cylindrical portion (11), said sleeve has an axial distance between an end portion relatively close to said step and said step, and said step and an end portion of said sleeve form an annular space therebetween for placing a weld ring when said body and said sleeve are welded; the barrel of the sleeve comprises a plurality of protruding parts, and the protruding parts form a structure of local clearance and local interference between the outer wall of the barrel (11) and the inner wall of the body; the protruding portion comprises a plurality of strip-shaped protrusions, the length of each strip-shaped protrusion is smaller than the length (L) of the barrel body portion (11) matched with the inner wall portion or the length of each strip-shaped protrusion is smaller than the length (L) of the inner wall portion matched with the barrel body portion (11), and certain axial distances are reserved between the two sides of each strip-shaped protrusion and the matching position.

4. A pipe fitting connecting structure according to claim 1 or 2, wherein the body is provided with a step portion (22) at the port portion at an inner wall portion of the tubular portion fitted to the cylindrical body portion (11), the sleeve has an axial distance between an end portion relatively close to the step portion and the step portion, and an annular space for placing a weld ring is formed between the step portion and the end portion of the sleeve, the annular space being used for placing the weld ring when the body and the sleeve are welded; the barrel of the sleeve comprises a plurality of protruding parts, and the protruding parts form a structure of local clearance and local interference between the outer wall of the barrel (11) and the inner wall of the body.

5. The pipe connecting structure according to claim 3, wherein the sleeve further comprises an inverted portion, the inverted portion is located at an opposite inner end of the sleeve, the inverted portion is formed by inward flanging or bending of the barrel portion, the inverted portion and the barrel portion form a positioning step portion, and the barrel portion, the inverted portion and the inverted portion are of an integral structure; the sleeve is relatively close to the end part of the step part of the body and further comprises a guide part, an axial distance is reserved between the guide part and the step part, an accommodating part is formed between the step part and the guide part, and the accommodating part is used for placing a welding ring when the body and the sleeve are welded.

6. The pipe connecting structure according to claim 4, wherein the sleeve further comprises an inverted portion, the inverted portion is located at an opposite inner end of the sleeve, the inverted portion is formed by inward flanging or bending of the barrel portion, the inverted portion and the barrel portion form a positioning step portion, and the barrel portion, the inverted portion and the inverted portion are of an integral structure; the sleeve is relatively close to the end part of the step part of the body and further comprises a guide part, an axial distance is reserved between the guide part and the step part, an accommodating part is formed between the step part and the guide part, and the accommodating part is used for placing a welding ring when the body and the sleeve are welded.

7. Tubular connection according to claim 1 or 2 or 5 or 6, characterized in that the wall thickness (D) of the eversion is between 0.5 and 2mm and the outer diameter (D1) of the base pipe is more than 2.5 times the outer diameter (D2) of the tubular part (24).

8. A tubular connection according to claim 3, characterized in that the wall thickness (D) of the eversion is between 0.5 and 2mm and the base pipe has an outer diameter (D1) which is more than 2.5 times the outer diameter (D2) of the tubular part (24).

9. A tubular connection according to claim 4, characterized in that the wall thickness (D) of the eversion is between 0.5 and 2mm and the outer diameter (D1) of the base pipe is more than 2.5 times the outer diameter (D2) of the tubular part (24).

10. A silencer, characterized in that, the silencer includes a sleeve and a body formed by spinning stainless steel pipes, the body includes a base pipe, a diameter-variable part and a tubular part, the sleeve is formed by spinning, the body and the sleeve are connected by the pipe fitting connection structure as the above claims 1-9.

11. An air conditioning system, characterized in that, the air conditioning system includes the first part, the first part includes the pipe connection structure of any one of the above claims 1-9, the sleeve end of the pipe connection structure is welded with the body, the air conditioning system also includes the copper pipe connected with the sleeve, the sleeve is welded with the copper pipe, the melting temperature of the solder used for welding the sleeve of the pipe connection structure and the copper pipe is lower than the melting temperature of the solder used for welding the sleeve and the stainless steel.

12. A refrigeration system comprising a first component, said first component comprising a tube fitting connection according to any one of claims 1-9, wherein one end of a sleeve of said tube fitting connection is welded to said body, said refrigeration system further comprising a copper tube connected to said sleeve, wherein said sleeve is welded to said copper tube, and wherein a melting temperature of a solder used to weld said sleeve to said copper tube of said tube fitting connection is lower than a melting temperature of a solder used to weld said sleeve to said stainless steel.