CN217977827U - Pipeline connecting structure - Google Patents

Abstract

The application relates to the technical field of pipeline connection, in particular to a pipeline connection structure. The pipe connection structure includes: one end of the first pipeline is provided with a first connecting part; one end of the second pipeline is provided with a second connecting part, and the second connecting part and the first connecting part are arranged at intervals; the hard sealing element is provided with a connecting hole; the hard sealing element is arranged between the first pipeline and the second pipeline, is respectively in hard sealing connection with the first pipeline and the second pipeline, and communicates the first pipeline with the second pipeline through the connecting hole; the connecting unit is sleeved on the outer walls of the first pipeline and the second pipeline, and is used for connecting the first pipeline and the second pipeline in a locking manner and respectively and hermetically abutting against the first connecting part and the second connecting part. The application has the advantages that the problems of aging, sealing failure and the like caused by the use of the sealing ring are avoided, and the service life and the sealing stability of the pipeline connecting structure are effectively improved.

Description

Pipeline connecting structure

Technical Field

The application relates to the technical field of pipeline connection, in particular to a pipeline connection structure.

Background

Pipeline connection structures are often used in the field of fluid transportation, and are used for connecting pipelines and components in fluid systems.

The existing pipeline connecting structure basically comprises a first pipeline, a second pipeline and a threaded sleeve, wherein the first pipeline is connected with an external pipeline or an element, the second pipeline is connected with the external pipeline or the element, the first pipeline is connected with the second pipeline through the threaded sleeve, and a sealing ring is adopted between the first pipeline and the second pipeline for sealing. After the application time is long, the sealing ring is easy to age and loosen, so that the sealing failure and other conditions are caused.

SUMMERY OF THE UTILITY MODEL

In view of the above, it is necessary to provide a pipe connection structure that is stable in sealing and has a long service life.

In order to solve the technical problem, the following technical scheme is adopted in the application:

a pipeline connecting structure comprises a first pipeline, a second pipeline, a hard sealing element and a connecting unit, wherein a first connecting part is arranged at one end of the first pipeline, a second connecting part is arranged at one end of the second pipeline, the first connecting part is opposite to the second connecting part, and a space is arranged between the first connecting part and the second connecting part; a connecting hole is formed in the hard sealing piece, the hard sealing piece is arranged between the first pipeline and the second pipeline and forms hard sealing connection with the first pipeline and the second pipeline, and the connecting hole of the hard sealing piece is communicated with the first pipeline and the second pipeline; the connecting unit is sleeved outside the first pipeline and the second pipeline, and the connecting unit is tightly abutted against the connecting part and is connected with the first pipeline and the second pipeline in a locking manner.

It can be understood that this application is through setting up hard sealing member to form hard sealing connection between messenger's first pipeline and the second pipeline, thereby avoid using ageing, the sealed inefficacy scheduling problem that the sealing washer brought, improved pipeline connection structure's life and sealed stability effectively.

In one embodiment, the first connecting part is provided with a first matching surface, and the second connecting part is provided with a second matching surface; a first sealing surface is arranged on the side part of one end of the hard sealing element, and a second sealing surface is arranged on the side part of the other end of the hard sealing element; the first matching surface is in sealing fit with the first sealing surface, and the second matching surface is in sealing fit with the second sealing surface.

It can be understood that the sealing area can be increased by the surface-to-surface matching mode, so that the sealing effect of the connecting structure is better.

In one embodiment, the first connecting part is further provided with a third matching surface, the second connecting part is further provided with a fourth matching surface, and the connecting unit is provided with a third sealing surface and a fourth sealing surface; and the third matching surface is in sealing fit with the third sealing surface, and the fourth matching surface is in sealing fit with the fourth sealing surface.

It can be understood that the sealing area can be increased by the surface-to-surface matching mode, so that the sealing effect of the connecting structure is better.

In one embodiment, one end of the first pipeline is formed with a first flaring, and the first connecting part is provided with a first flaring; the inner side surface of the first flaring forms a first matching surface, and the outer side surface of the first flaring forms a third matching surface.

It can be understood that, by arranging the first flared opening as the first connecting portion, and the inner side face and the outer side face of the first flared opening can form corresponding matching faces, the structure is simple.

In one embodiment, one end of the second pipe is formed with a second flare, and the second connecting portion is provided as the second flare; wherein an inner side surface of the second flare forms the second mating surface and an outer side surface of the second flare forms the fourth mating surface.

It will be appreciated that by providing the second flared end as the second connection portion, and the inner and outer side surfaces of the second flared end forming the corresponding mating surfaces, the structure is simple.

In one embodiment, the first mating surface, the second mating surface, the third mating surface and the fourth mating surface are provided as tapered surfaces; the first sealing surface, the second sealing surface, the third sealing surface and the fourth sealing surface are all provided with conical surfaces.

So set up, can be so that laminating between the face is inseparabler, has improved sealed effect effectively.

In one embodiment, the end face of the hard seal facing the first pipe and/or the second pipe is provided with a plane or an arc surface; and the plane or the cambered surface is connected with the corresponding matching surface.

It can be understood that the flat surface or the cambered surface can prevent sharp corners on the sealing surface from colliding with the pipeline to cause damage to the part.

In one embodiment, the connecting unit comprises a connecting sleeve and a connecting head; the connecting sleeve is sleeved on the first pipeline and abutted against the first connecting part, and the connecting head is sleeved on the second pipeline and abutted against the second connecting part; the connecting sleeve is detachably connected with the connecting head, and the connecting sleeve is provided with an operating part on the connecting head.

It can be understood that the detachable connection is arranged, so that the pipeline connecting structure can be conveniently mounted and detached, and the pipeline connection is simpler, more convenient and easier to operate.

In one embodiment, the aperture of the connection hole of the hard sealing member is R1, the inner diameter of the first pipe or the second pipe is R2, and the following relationship is satisfied between R1 and R2: r1 and R2 are more than or equal to 0.7.

It can be understood that the diameter of the connecting hole is larger than or equal to 0.7 times of the inner diameter of the pipeline, so that throttling caused by the fact that the diameter of the connecting hole is too small is effectively avoided.

In one embodiment, R1: R2 is more than or equal to 1.

It can be understood that the aperture of the connecting hole is larger than or equal to the inner diameter of the pipeline, and throttling caused by the fact that the aperture of the connecting hole is too small is further avoided.

Compared with the prior art, the pipeline connecting structure in this application is through setting up hard sealing member to make and form hard sealing connection between first pipeline and the second pipeline, thereby avoid using ageing, the sealed inefficacy scheduling problem that the sealing washer brought, improved pipeline connecting structure's life and sealed stability effectively.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic structural diagram of an embodiment of a pipe connection structure provided in the present application.

Fig. 2 is a partial enlarged view of a portion a in fig. 1 provided in the present application.

FIG. 3 is a half-sectional view of an embodiment of a pipe connection structure provided herein.

Fig. 4 is a schematic structural diagram of another embodiment of the pipe connection structure provided in the present application.

Fig. 5 is a partial enlarged view of fig. 3 at B provided in the present application.

Fig. 6 is a schematic structural diagram of a hard seal provided in the present application.

Fig. 7 is a schematic structural diagram of the connecting sleeve provided in the present application.

Fig. 8 is a schematic structural diagram of a connecting head provided in the present application.

Reference numerals: 100. a pipe connection structure; 10. a first conduit; 11. a first connection portion; 111. a first mating surface; 112. a third mating surface; 12. a first flare; 13. a first convex portion; 20. a second pipe; 21. A second connecting portion; 211. a second mating surface; 212. a fourth mating surface; 22. a second flare; 23. a second convex portion; 30. a hard seal; 31. connecting holes; 32. a first sealing surface; 33. a second sealing surface; 34. An end face; 40. a connection unit; 41. connecting sleeves; 411. a third sealing surface; 412. a first operation unit; 42. A connector; 421. a fourth sealing surface; 422. a second operation part.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of embodiments in many different forms than those described herein and that modifications may be made by one skilled in the art without departing from the spirit and scope of the application and it is therefore not intended to be limited to the specific embodiments disclosed below.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or intervening components may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used in the description of the present application are for illustrative purposes only and do not represent the only embodiments.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise.

In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may mean that the first feature is in direct contact with the second feature or that the first feature is in indirect contact with the second feature via an intermediate medium. Also, a first feature "on," "above," and "over" a second feature may be directly on or obliquely above the second feature, or may simply mean that the first feature is at a higher level than the second feature. A first feature "under," "beneath," and "under" a second feature may be directly under or obliquely under the second feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

Unless defined otherwise, all technical and scientific terms used in the specification of the present application have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the description of the present application, the term "and/or" includes any and all combinations of one or more of the associated listed items.

As shown in fig. 1 or fig. 4, the present application provides a pipeline connecting structure 100, and the pipeline connecting structure 100 is used for connecting pipelines and elements.

Specifically, the pipe connection structure 100 includes a first pipe 10, a second pipe 20, a hard seal 30, and a connection unit 40. One end of the first pipeline 10 is provided with a first connecting portion 11, one end of the second pipeline 20 is provided with a second connecting portion 21, and the second connecting portion 21 and the first connecting portion 11 are arranged at intervals. The hard sealing element 30 is provided with a connecting hole 31, the hard sealing element 30 is arranged between the first pipeline 10 and the second pipeline 20, and is respectively in hard sealing connection with the first pipeline 10 and the second pipeline 20, and the first pipeline 10 and the second pipeline 20 are communicated through the connecting hole 31. The connecting unit 40 is sleeved on the outer walls of the first pipeline 10 and the second pipeline 20, and the first pipeline 10 and the second pipeline 20 are fixedly connected, so that the first connecting portion 11 and the second connecting portion 21 are tightly abutted to the hard sealing member 30, and the connecting unit 40 is tightly abutted to the first connecting portion 11 and the second connecting portion 21. In this way, the hard sealing connection between the first pipeline 10 and the second pipeline 20 is realized by using the hard sealing member 30, so that the problems of aging, sealing failure and the like caused by using a sealing ring (soft) are avoided, and the service life and the sealing stability of the pipeline connecting structure 100 are effectively improved. Meanwhile, the first pipeline 10 and the second pipeline 20 are preferably made of materials with low hardness, such as copper pipes, aluminum pipes and the like, so that better hard sealing performance can be realized.

As shown in fig. 2 or 5, the first connecting portion 11 is provided with a first mating surface 111, and the second connecting portion 21 is provided with a second mating surface 211. As shown in fig. 6, one end side of the hard seal 30 is provided with a first sealing surface 32, and the other end side of the hard seal 30 is provided with a second sealing surface 33. As shown in fig. 2, the first mating surface 111 is in sealing engagement with the first sealing surface 32, and the second mating surface 211 is in sealing engagement with the second sealing surface 33. Therefore, by the abutting mode between the surfaces, the sealing contact area between the first connecting portion 11 and the hard sealing member 30 and the sealing contact area between the second connecting portion 21 and the hard sealing member 30 are effectively increased, and the sealing effect between the hard sealing member 30 and the first connecting portion 11 and the second connecting portion 21 is further improved.

The first mating surface 111 may be a tapered surface or a flat surface. In the present embodiment, as shown in fig. 2, the first mating surface 111 is a tapered surface, and correspondingly, the first sealing surface 32 is also a tapered surface. In this way, by providing the first mating surface 111 as a tapered surface, the first mating surface 111 and the first sealing surface 32 can be abutted more tightly, and the sealing effect therebetween can be further improved. Also, the second mating surface 211 may be a tapered surface or a flat surface. In the present embodiment, as shown in fig. 2, the second mating surface 211 is a tapered surface, and correspondingly, the second sealing surface 33 is also a tapered surface. In this way, by providing the second mating surface 211 as a tapered surface, the second mating surface 211 and the second sealing surface 33 can be abutted more tightly, and the sealing effect therebetween can be further improved.

As shown in fig. 2 or fig. 5, the first connecting portion 11 is further provided with a third mating surface 112, the second connecting portion 21 is further provided with a fourth mating surface 212, the third mating surface 112 is disposed opposite to the first mating surface 111, and the fourth mating surface 212 is disposed opposite to the second mating surface 211. As shown in fig. 7, the connecting sleeve 41 is further provided with a third sealing surface 411; as shown in fig. 8, a fourth sealing surface 421 is further provided on the connecting head 42. As shown in fig. 2, the third mating surface 112 is in sealing engagement with the third sealing surface 411, and the fourth mating surface 212 is in sealing engagement with the fourth sealing surface 421. Therefore, the sealing contact area between the first connecting part 11 and the connecting sleeve 41 and between the second connecting part 21 and the connecting head 42 is effectively increased through the abutting mode between the surfaces, and the sealing effect between the connecting sleeve 41 and the first connecting part 11 and between the connecting head 42 and the second connecting part 21 is further improved.

The third mating surface 112 may be a tapered surface or a flat surface, and in this embodiment, as shown in fig. 2, the third mating surface 112 is a tapered surface, and correspondingly, the third sealing surface 411 is also a tapered surface. In this way, by setting the third mating surface 112 as a tapered surface, the abutment between the third mating surface 112 and the third sealing surface 411 can be made tighter, and the sealing effect therebetween can be further improved. Likewise, the fourth mating surface 212 may be a tapered surface or a flat surface. In the present embodiment, as shown in fig. 2, the fourth mating surface 212 is a tapered surface, and correspondingly, the fourth sealing surface 421 is also a tapered surface. In this way, by providing the fourth mating surface 212 as a tapered surface, the abutment between the fourth mating surface 212 and the fourth sealing surface 421 can be made tighter, and the sealing effect between the two can be further improved.

As shown in fig. 1 and 2, in an embodiment, one end of the first pipe 10 is formed with a first flared end 12, and the first connecting portion 11 is provided as the first flared end 12; wherein the inner side surface of the first flared end 12 forms a first mating surface 111 and the outer side surface of the first flared end 12 forms a third mating surface 112. This makes the machining of the first connection portion 11 simple and eliminates the need to re-machine the first mating face 111 and the third mating face 112.

In the present embodiment, the first flare 12 is shaped as a flare, and the inner diameter of the first flare 12 becomes gradually larger along the axial direction of the first pipe 10 and from the direction away from the first pipe 10. Thus, the inner side surface of the first flared end 12 forms a first mating surface 111, that is, the first mating surface 111 is a conical surface. The outer side surface of the first flared end 12 forms a third mating surface 112, that is, the third mating surface 112 is a conical surface.

As shown in fig. 1 and 2, in an embodiment, one end of the second pipe 20 is formed with a second flared opening 22, and the second connecting portion 21 is provided as the second flared opening 22; wherein the inner side surface of the second flared end 22 forms a second mating surface 211 and the outer side surface of the second flared end 22 forms a fourth mating surface 212. This makes the processing of the second connection portion 21 simple.

In the present embodiment, the second flare 22 is shaped as a flare, and the inner diameter of the second flare 22 becomes gradually larger along the axial direction of the second pipe 20 and from the direction away from the second pipe 20. The inner side surface of the second flared end 22 forms a second mating surface 211, that is, the second mating surface 211 is a conical surface; the outer side surface of the second flared end 22 forms a fourth mating surface 212, i.e., the fourth mating surface 212 is a tapered surface.

As shown in fig. 4 and 5, in another embodiment, one end of the first pipe 10 is formed with a first protrusion 13 protruding in a radial direction of the first pipe 10, and the first connection part 11 is provided as the first protrusion 13; along the axial direction of the first pipe 10, two opposite surfaces of the first convex portion 13 form a first mating face 111 and a third mating face 112, respectively. One end of the second duct 20 is formed with a second protrusion 23 protruding in the radial direction, and the second connection portion 21 is provided as the second protrusion 23; along the axial direction of the second pipe 20, two opposite surfaces of the second convex portion 23 form a second mating face 211 and a fourth mating face 212, respectively.

As shown in fig. 6, the hard seal 30 is substantially cylindrical, and the hard seal 30 is provided as a metal member. In this embodiment, the hard seal 30 is configured as an aluminum pipe, a copper pipe, an aluminum alloy pipe, or the like, which can be specifically selected according to actual requirements.

Further, the inner diameter of the connection hole 31 is R1, the hole diameters of the first pipeline 10 and the second pipeline 20 are R2, and R1 and R2 satisfy that R1 is more than or equal to 0.7R2. Thus, the aperture of the connection hole 31 can be prevented from being too small, so that the fluid can be severely throttled at the pipeline connection structure 100 after the pipeline connection.

Preferably, R1 ≧ R2, so that the aperture of the connection hole 31 can be further prevented from being smaller than the pipe diameter, which causes throttling of the fluid at the pipe connection structure 100 after the pipe connection.

As shown in fig. 6, the end surface 34 of the hard seal 30 facing the first pipe 10 and/or the second pipe 20 is configured as a flat surface or an arc surface, and the flat surface or the arc surface is connected with a corresponding conical surface. The end face of the hard sealing element 30 is set to be a plane or an arc face, which can avoid the situation that the end face of the hard sealing element 30 is damaged by collision with a pipeline due to sharp corners.

As shown in fig. 3, the connection unit 40 includes a connection sleeve 41 and a connection head 42, the connection sleeve 41 is sleeved on the first pipeline 10 and abuts against the first connection portion 11, and the connection head 42 is sleeved on the second pipeline 20 and abuts against the second connection portion 21; wherein, the connecting sleeve 41 is detachably connected with the connecting head 42. Therefore, the connection and the disassembly between the pipelines and the elements can be facilitated, and the device is simple, convenient and easy to operate.

In one embodiment, the connecting sleeve 41 and the connecting head 42 are connected by screw threads. Of course, the connection between the connection sleeve 41 and the connection head 42 is not limited to a threaded manner, and in other embodiments, the connection may be a detachable connection such as a snap.

Further, each of the connecting sleeve 41 and the connecting head 42 is provided with an operating portion, so that the connecting sleeve 41 and the connecting head 42 can be operated by the operating portions. Specifically, the outer side surface of the connecting sleeve 41 is provided with a first operating part 412, and the first operating part 412 is used for being clamped and held by an external tool or an operator to install the connecting sleeve 41. A second operation part 422 is provided on the outer side surface of the connection head 42, and the second operation part 422 is used for an external tool or an operator to hold and hold so as to facilitate the connection between the connection sleeve 41 and the connection head 42.

Preferably, the first operating portion 412 is provided as a plane, and the number of the planes is multiple, and the multiple planes are arranged at intervals in the circumferential direction of the outer side surface of the connecting sleeve 41. Similarly, the second operation portion 422 is also provided with a plurality of planes, and the plurality of planes are provided at intervals in the circumferential direction of the outer side surface of the connection head 42. As shown in fig. 7 and 8, a portion of the connecting sleeve 41 abutting against the first connecting portion 11 is provided with a third sealing surface 411 attached to the third mating surface 112. The portion of the connecting head 42 abutting against the second connecting portion 21 is provided with a fourth sealing surface 421 attached to the fourth mating surface 212.

In the installation process, the connection sleeve 41 is sleeved on the first pipeline 10, the inside of the connection sleeve 41 abuts against the first connection portion 11, and the third sealing surface 411 is attached to the third mating surface 112. The hard sealing member 30 is disposed in the connecting sleeve 41 and abuts against the first connecting portion 11, and the first sealing surface 32 is attached to the first mating surface 111. The second pipe 20 is placed in the connection sleeve 41, the second connection portion 21 abuts against the hard sealing member 30, the second matching surface 211 is in sealing fit with the second sealing surface 33, finally the connection head 42 is sleeved on the second pipe 20, the connection head 42 abuts against the second connection portion 21 and is detachably connected with the connection sleeve 41, the first sealing surface 32 is tightly fitted with the first matching surface 111, the second sealing surface 33 is tightly fitted with the second matching surface 211, the third sealing surface 411 is tightly fitted with the third matching surface 112, and the fourth matching surface 212 is tightly fitted with the fourth sealing surface 421, and finally the two pipes are in sealing connection.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims (10)

1. A pipe connecting structure, characterized by comprising:

the device comprises a first pipeline, a second pipeline and a third pipeline, wherein one end of the first pipeline is provided with a first connecting part;

one end of the second pipeline is provided with a second connecting part, and the second connecting part and the first connecting part are arranged at intervals;

the hard sealing element is provided with a connecting hole; the hard sealing element is arranged between the first pipeline and the second pipeline, is in hard sealing connection with the first pipeline and the second pipeline respectively, and communicates the first pipeline with the second pipeline through the connecting hole;

the connecting unit is sleeved on the outer walls of the first pipeline and the second pipeline, connected between the first pipeline and the second pipeline in a locking mode and respectively abutted against the first connecting portion and the second connecting portion in a sealing mode.

2. The pipe connecting structure according to claim 1, wherein a first mating surface is provided on the first connecting portion, and a second mating surface is provided on the second connecting portion; a first sealing surface is arranged on the side part of one end of the hard sealing element, and a second sealing surface is arranged on the side part of the other end of the hard sealing element;

the first matching surface is in sealing fit with the first sealing surface, and the second matching surface is in sealing fit with the second sealing surface.

3. The pipe connecting structure according to claim 2, wherein a third mating surface is further provided on the first connecting portion, a fourth mating surface is further provided on the second connecting portion, and a third sealing surface and a fourth sealing surface are provided on the connecting unit;

the third matching surface is in sealing fit with the third sealing surface, and the fourth matching surface is in sealing fit with the fourth sealing surface.

4. A pipe connecting structure according to claim 3, wherein one end of the first pipe is formed with a first flare, and the first connecting portion is provided as the first flare;

wherein an inner side surface of the first flare forms the first mating surface and an outer side surface of the first flare forms the third mating surface.

5. The pipe connecting structure according to claim 3, wherein one end of the second pipe is formed with a second flare, and the second connecting portion is provided as the second flare;

wherein an inner side surface of the second flare forms the second mating surface and an outer side surface of the second flare forms the fourth mating surface.

6. The pipe connecting structure according to claim 3, wherein the first mating surface, the second mating surface, the third mating surface, and the fourth mating surface are provided as tapered surfaces;

the first sealing surface, the second sealing surface, the third sealing surface and the fourth sealing surface are all provided with conical surfaces.

7. The pipe connection structure according to claim 2, wherein the end face of the hard seal facing the first pipe and/or the second pipe is provided as a flat face or an arc face;

wherein, the plane or the cambered surface is connected with the corresponding matching surface.

8. The pipe connecting structure according to claim 1, wherein the connection unit includes a connection sleeve and a connection head; the connecting sleeve is sleeved on the first pipeline and abutted against the first connecting part, and the connecting head is sleeved on the second pipeline and abutted against the second connecting part;

the connecting sleeve is detachably connected with the connecting head; the connecting sleeve and the connecting head are both provided with operating parts.

9. The pipe connection structure according to claim 1, wherein a bore diameter of the connection hole is R1, an inner diameter of the first pipe or the second pipe is set to R2, and R1 and R2 satisfy the following relationship:

R1:R2≥0.7。

10. the pipe connecting structure according to claim 9, wherein R1: R2 is not less than 1.

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