DE29521617U1 - Pipe with a connection section and pipe connection - Google Patents

Description

Walterscheid Pipe Connection Technology GmbH 08 September 1997

Hauptstraße 150 Hw/kau (0592)

53797 Lohmar P94015DE20

Pipe with a connecting section and pipe connection

Description

The invention relates to a pipe with a connecting section attached to at least one of its two ends by deformation of the pipe end, which has two clamping surfaces designed as conical surfaces and directed against each other, the connecting section being intended for receiving with its first clamping surface in a conical bore designed according to the standard for cutting rings (DIN 3861, as of May 1994, bore shape W) for different pipe outer diameters, this being part of a connecting body or a connecting bore of another body and for supporting with its second clamping surface against a conical surface having a cone angle of 90° and designed as a bore of a union nut that fits the connecting body or a union screw that fits the connecting bore and can be pushed over the pipe, and also a pipe connection.

A pipe for a pipe connection with a connecting section formed from the pipe material according to the contours of a standardized cutting ring is described in DD 240 059 Al, whereby the cone angle of the first clamping surface is smaller than that of the cone bore of the screw connection piece to which it is assigned. This is intended to create a linear contact of the first clamping surface at the smallest diameter of the cone bore in order to increase the sealing effect. The second clamping surface, which works together with the union nut, is pressed on and the cone piece extending from it, which runs forward to the end of the pipe, is formed with the first clamping surface. The disadvantage here is that

is that the high axial screwing forces result in high surface pressures, which can lead to settlement phenomena that do not permanently meet the high sealing requirements. The linear support of the pipe in the socket also leads to settlement and, as a result, leaks when the pipe is subjected to alternating bending loads.

Furthermore, US 48 71 199 describes a pipe connection and a method for producing the same, in which the conical bore has a cone angle of 30° to 40°. The surface of the nut that works with it preferably runs at a right angle to the longitudinal axis of the nut, but it can also be designed as a shoulder that runs at an angle of 45° to the axis. The connecting section of the pipe is produced by axially compressing it in a multi-part tool. This involves deformation in such a way that the pipe folds in the area of the connecting section. The folds should remain pronounced, because during later assembly the folds should be further deformed by tightening the nut. These folds should provide a spring-loaded compensation in order to remain tight even in the event of high internal pressure peaks.

The disadvantage of such a design is that the internal pressure and especially the occurrence of vibrations can cause the connection to settle because the elastic spring travel is not sufficient, so that it becomes leaky and has to be tightened.

DIN 2353, as of June 1991, specifies solderless pipe fittings with cutting rings, in which the dimensions for various designs are determined for several series. The design of the corresponding union nuts is described in DIN 3870, as of May 1985, and that of the threaded pins in DIN 3853, as of November 1982. The corresponding cutting rings are defined in DIN 3861, as of May 1994, or sealing cones in DIN 3865, as of May 1994. The union nuts or union screws and connecting bodies take into account that even when the connection is tightened, a corresponding axial clearance remains between the nut and the connecting body in order to prevent retightening.

Accordingly, the sealing cone or the cutting ring are axially longer than the depth of the holes in the connecting body and the union nut require.

The invention is based on the object of creating a pipe for a pipe connection with a connecting section, a pipe connection and a method for producing the connecting section of the pipe, which ensure that a tight connection is provided and maintained even under high pressures and oscillating stress, and can also be produced cost-effectively.

This object is achieved according to the invention by a pipe in which the connecting section is produced by upsetting the pipe in a tool having at least two partial tools that can be adjusted relative to one another in the direction of the pipe axis, increasing the pressing force until a predetermined upsetting path is reached, the first partial tool of which has a first conical pressing surface designed in accordance with the conical bore as part of a bore and a stop surface for the contact with the end face of the pipe and the second partial tool of which has a second conical pressing surface designed as a bore, which has a cone angle of 90°, the free pipe length to be subjected to the upsetting process, with which the pipe protrudes beyond the smallest diameter of the second conical pressing surface to the stop surface, being the length of a sealing cone standardized according to DIN 3865, as of May 1994, which is the difference between the lengths L ₃ and L ₁ for the embodiment A, Figure 1 plus the length resulting from DIN 3861, as of May 19 94, bore shape W, resulting length of the tapered bore, plus the length of any pipe projection provided which is shorter than the cylindrical bore section adjoining the standardized tapered bore, plus the upsetting path which is a minimum of 6 mm and a maximum of 8.5 mm, and that the relative path which the part tools have carried out to one another in the direction of the pipe axis during manufacture corresponds to the upsetting path, and wherein the upsetting path assumes the maximum value towards the largest pipe outside diameter used.

A pipe connection according to the invention to solve this problem is characterized by the use of the aforementioned pipe with a connecting section of a connecting body, with a tapered conical bore starting from one end face of the same, to the smallest diameter of which a first circular cylindrical bore, which has a bore shape W according to DIN 3861, status May 1994, is connected, and with a threaded section attached to the outer surface starting from the first end face and a nut that can be screwed onto the threaded section with a threaded bore matching the threaded section of the connecting body, a conical surface adjoining thereto and tapering in the opposite direction to the conical bore of the connecting body and with a bore through which the pipe is guided.

These designs ensure that the connecting section is not deformed during assembly or repeated assembly and that the internal pressures and oscillating stresses do not cause the connection to loosen and thus become leaky. The connecting section is part of a screw connection system in which the nozzle, union nut and pipe have coordinated spring constants. Neither the assembly forces nor the loads caused by pressure pulses and vibrations cause the connection to settle or even loosen. This ensures secure clamping. The axial clamping force is dimensioned in such a way that secure and tight clamping is maintained, taking the maximum operating pressure into account. According to DIN regulations, series are standardized, each of which is designed according to certain maximum permissible operating pressures.

It was found that the manufacture of a pipe with a connecting section that provides secure support can be achieved with a specified compression stroke of 6 mm to 8.5 mm, whereby the compression stroke can be used for the entire diameter range of the standardized series. In this case, a deformation is achieved to such an extent that no settling of the connecting section occurs when assembly or reassembly is carried out. The compression stroke is in narrow

Limits of 2.5 mm are to be dimensioned depending on the pipe's external diameter; the compression path increases with increasing diameter. The material of the pipe and the wall thickness are not important here. They are only important for the pressing force.

If the specified compression path is observed, no further axial deformation of the connecting section occurs during assembly at the maximum clamping force that can be achieved.

The design of the conical bore of the connecting body and the nut at 24° or 90° corresponds to the design usual for cutting ring screw connections according to DIN 3861 or 3870. The tolerances for the dimensioning of the conical angle also follow from this. The tolerance for the conical angle of the conical bore of the connecting body is ± 30 min. and for the conical angle of the conical surface of the nut is ± 20 min.

In a preferred embodiment, the conical surface of the nut merges into the bore with a curved surface. This reduces the notch stress.

In addition to the possibility of having the connecting section start directly at the pipe end surface, it is also possible to provide an arrangement in which a circular cylindrical pipe section is placed upstream of the first clamping surface, which is associated with the tapered bore. When assembled, this sits in a circular cylindrical bore of the connecting body downstream of the tapered bore.

It is possible that a step is provided between the first clamping surface and the outer surface of the pipe section. The space created by the step can be used to accommodate a seal.

To limit the tightening, the largest diameter of the first clamping surface of the connecting section, which corresponds to the tapered bore, ends in an annular contact shoulder. This comes into contact with the end face of the connecting body when the maximum tightening path is reached.

In a specific embodiment of the invention, an improved seal can also be achieved by arranging a sealing agent having a liquid or pasty initial state between the connecting section and/or the pipe sections adjoining it on both sides and the associated areas of the connecting body and the nut. It is also possible to improve the fine seal by arranging a seal in the form of a disk between the end face of the pipe section arranged in front of the first clamping surface and the annular shoulder of the bore of the connecting body. Furthermore, to achieve an improved fine seal, a seal can be provided on the outside of the connecting section of the pipe, which has a sealing projection clamped between the end face of the connecting body and the contact shoulder of the connecting section.

Preferred embodiments of the pipe connection according to the invention and of a tool as well as the manufacturing process of deforming the pipe to produce a connecting section are shown schematically in the drawing and explained using the same.

It shows

Figure 1 shows a first embodiment of a pipe connection, in which the connecting section of the pipe extends directly from a pipe end surface,

Figure 2 shows an embodiment of the pipe connection in which

a circular cylindrical pipe section is installed upstream of the connecting section of the pipe,

Figure 3 shows a modified embodiment compared to Figure 2.

shape with a shoulder to limit the tightening path when the maximum permissible clamping force is reached/exceeded,

Figure 4 shows an embodiment similar to Figure 3, but in a free space between the clamping surface

of the connecting section and the conical bore a seal is inserted,

Figure 5 shows an embodiment modified from Figure 4, in which a liquid or pasty sealant is applied to parts of the connecting section and the pipe sections connected to it,

Figure 6 shows an embodiment in which a sealing disc is inserted between the pipe end face and the step of the connecting body,

Figure 7 shows an embodiment in half-longitudinal section, with a nut with a shortened thread and a seal between the connecting body and nut,

Figure 8 shows an embodiment according to Figure 3, wherein

a seal sits on the outer surface of the connecting section, and next to it a cross-section through the annular seal as a single part,

Figure 9 shows an embodiment with a sealing element inserted before deformation,

Figure 10 a tool for producing the pipe connection, in the upper half before the deformation of the pipe and in the lower half after the deformation of the pipe and

Figure 11 a modified embodiment of the tool

according to Figure 9 with additional support of the pipe in the bore, also in the upper half before deformation and in the lower half after completion of the deformation of the pipe to create the fastening section.

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Figure 1 shows an assembled pipe connection with the connecting body 1, the nut 2 screwed onto it and the pipe 3 held between the two with the aid of the connecting section 4.

A conical bore 6 extends from the front face 5 of the connecting body 1, centered on the longitudinal axis 31 of the pipe connection shown in half section, which tapers inwards from the front face 5. The conical bore 6 merges at its smallest diameter into a circular cylindrical bore 7, which ends with an annular shoulder 8 in the through-bore 9, which is reduced in diameter for this purpose. A threaded section 10 is provided on the outer surface of the connecting body 1, which extends from the front face 5. The conical bore 6 of the connecting body 1 has a cone angle A of 24°. The permissible tolerance range is ± 30 min.

The nut 2 screwed onto the connecting body 1 has a bore 11 which is provided with a thread 12 which is designed to match the thread 10 of the connecting body 1. The bore 11 is followed by a conical surface 13, the conical angle of which is designated B and is 90° with a tolerance of ± 20 min. The conical surface 13 runs opposite to the conical bore 6 of the connecting body 1. The conical surface 13 merges into the bore 15 with a curved surface 14. The nut 2 can be provided with wrench surfaces on the outer surface in order to be able to tighten it. The connecting body 1 can also be provided with a wrench surface which is connected to the thread 10. In the case of a straight screw connection, two of the aforementioned connections are provided in the form of the conical bore, which are connected to one another via the through-bore 9 and are directed in opposite directions. The lengths of the thread sections 10, 12 are dimensioned so that, when tightened, an overlap is achieved with a number of thread turns that is designed according to the maximum permissible axial clamping force for tightening the connection.

The pipe 3 with its connecting section 4 is accommodated between the conical bore 6 and the conical surface 13. The connecting

The connecting section 4 is formed by forming it out of the normal pipe diameter by axial compression. The connecting section 4 has a first clamping surface 16 which is designed to be opposite to the conical bore 6 and is in surface contact with it. The conical first clamping surface 16 extends directly from the end face 17 of the pipe 3. The first clamping surface 16 ends in a contact shoulder 18 which runs radially outwards and serves to limit the tightening of the nut 2 and thus of the connecting section 4. The tightening is limited by the fact that the contact shoulder 18 comes into contact with the end face 5 of the connecting body 1. Following the contact shoulder 18, there is an exposed section which merges into a section which runs towards the normal wall of the pipe 3 and on whose outer surface the second clamping surface 19 is attached, which is designed as a conical surface and whose cone angle is 90°. This is followed by the pipe section 20 of the pipe 3 which is led outwards through the bore 15 of the nut 2.

In the embodiment of the pipe connection according to Figure 2, the first clamping surface 16 of the connecting section 4 is preceded by a circular cylindrical pipe section 21, which sits with its outer surface in the circular cylindrical bore 7 of the connecting body 1 and whose end face 17a ends in front of the annular shoulder 8. In this solution, too, there is surface contact between the conical bore 6 and the first clamping surface 16 as well as the conical surface 13 of the nut 2 and the second clamping surface 19 of the connecting section 4 of the pipe 3. The connecting section 4, however, does not have a stop surface for running into the end face 5 of the connecting body 1.

Figure 3 shows an embodiment that essentially corresponds to that of Figure 2. A cylindrical tube section 21 is also provided in front of the first clamping surface 16, which is provided with the end face 17a that ends in front of the annular shoulder 8. The fastening section 4 is in this case provided with a contact shoulder 18 that serves to limit the tightening of the nut 2 and thus of the connecting section 4 to the connecting body 1 by being on the end face 8 of the connecting

ing body 15 comes into contact. In this embodiment too, the second clamping surface 19 lies flat against the conical surface 13 of the nut 2.

In the embodiment according to Figure 4, the first clamping surface 16 is shorter than the embodiment according to Figure 3. The outer surface 22 of the cylindrical pipe section 21 merges into the first clamping surface 16 with a step 23, so that a free space is formed between the step 23 and the outer surface 22 and the conical bore 6, into which a seal 24 is inserted. The second clamping surface 19 is also conical, like the conical surface 13 of the nut 2, and is in surface contact with it. The pipe 3 is led out of the nut 2 with the pipe section 20.

The seal 24 improves the fine sealing of the pipe connection. Compared to solutions in which the connection between the pipe and the connecting body or nut is made by a separate cutting or clamping ring, this is improved by eliminating gaps.

Figure 5 shows a design that differs from Figure 4 in terms of the fine seal. Between the first clamping surface 16, which is seated flat in the conical bore 6, and the outer surface 22 of the upstream cylindrical pipe section 21, a sealing agent is provided that is applied to these surfaces in pasty or liquid form. The resulting seal is designated 24a. Likewise, between the pipe section 20 of the pipe 3 that leads out of the nut 2 and the bore 15 of the nut, there is a seal 24a that is applied to the outer surface of the pipe 3 in pasty or liquid form.

Figure 6 shows an arrangement in which the pipe 3 with the connecting section 4 is clamped between the connecting body 1 and the nut 2 and whose pipe section 21, which is seated in the bore 7 of the connecting body 1, is supported with its end face 17a against a seal 24b in the form of a flat ring, which with its other side is against the ring shoulder 8.

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I* ·

15

the hole 7.

Figure 7 shows a further variant of the pipe connection in which the threads of the connecting body 1 and the nut 2 are shortened and only overlap in the tightened state by a length that is measured according to the maximum permissible axial clamping force. Furthermore, the nut 2 has a surface 41 in its bore that runs radially with respect to the longitudinal axis 31. A seal 24c is clamped between this surface 41 and the end face 5 of the connecting body 1, which seals the gap between the connecting body 1, the connecting section 4 of the pipe 3 and the nut 2.

Figure 8 shows a further embodiment of the seal, in which a seal 24d is placed on the outside of the connecting section 4 of the pipe 3. This has, as can be seen in particular from the illustration of the seal 24d as a single part, a radially inwardly directed annular sealing projection 42 which, in the tightened state of the pipe connection, is clamped between the end face 5 of the connecting body 1 and the radial bearing shoulder 18 of the connecting section 4 of the pipe 3.

Figure 9 shows a further, modified embodiment of the seal, wherein between the conical bore of the connecting body 1 and the cylindrical first conical clamping surface of the connecting section a seal 43 is arranged, which was assigned to the pipe 3 and deformed before the forming.

The shape of the connecting section 4 according to Figures 1 to 9 was created by compressing a pipe in a tool, as shown for example in Figure 9. The upper half shows the mutual assignment of the one-piece nozzle 26 to the multi-part clamping jaw 32 before the deformation of the pipe 36. In the position shown below the longitudinal axis 31, the nozzle 26 and clamping jaw 32 are in an approximate, i.e. retracted, position, with the connecting section 4 shown in its formed form. The nozzle 26 comprises a projection 27 protruding on one side. Starting from the

The front face 30 of the extension 27 has a first conically tapering pressing surface 28 which merges into a circular cylindrical blind bore 29 which ends in the bottom surface 29a. The nozzle 26 can be moved in the direction of the clamping jaw 32 along the longitudinal axis 31 by a power drive, e.g. a hydraulic cylinder. The clamping jaw 32 is constructed, for example, from two halves 32a, 32b and radially clamps the pipe 36 with the clamping bore 35 so that it is held axially immovable. The clamping jaw 32 has a bore 33 which is larger than the outer diameter of the extension 27 of the nozzle 26 so that the latter can enter the bore 33. The bore 33 merges into a second conical pressing surface 34 which tapers in the opposite direction to the taper of the conical pressing surface 28 of the nozzle 26 and which ends in the clamping bore 35 which bears against the outer surface of the pipe 36 and has its smallest diameter D _min> . For this purpose, the clamping bore 35 can be provided with friction-increasing means and can engage the surface of the pipe 36.

In Figure 10, upper half, the pipe 36 is held radially and thus also axially clamped by the two clamping jaws 32a, 32b. The immersion length of the pipe 36 or the length by which it projects axially in the direction of the nozzle 26 beyond the clamping jaws 32 is predetermined. The length L is made up of the sum of the lengths of a standardized sealing cone, which results from the difference between the lengths L ₃ and L ₁ for the design A, Figure 1 according to DIN 3865, status May 1994, plus the length of the tapered bore resulting from DIN 3861, status May 1994, bore shape W, as well as the length of any pipe projection (length Y) that is provided, which is shorter than the cylindrical bore section adjoining the standardized tapered bore, and the length of the compression path X, which is selected from 6 mm to 8.5 mm depending on the pipe outer diameter. The pipe projection is therefore calculated for a pipe with an outer diameter of 10 mm or 38 mm for the S or L series and without pipe projection (Y = 0) as follows:

Type L3 5 Ll ,5 Lkeg. Y X 5 L ,41 10L 26 20 5.41 0 7 18 ,85 38 S 48, 39 6.35 0 8th, 23

The pipe 36 rests with its front face 37 on the bottom 29a of the blind bore 29. By moving the nozzle 26 to the right by the compression path of 6 mm to 8.5 mm, the wall of the pipe 36 bulges outwards and rests on the conical pressing surface 28 of the nozzle 26 or the conical pressing surface 34 of the clamping jaw 32. At the same time, a stop surface is compressed in the direction of the front face 30 of the nozzle 27. The pressing force P with which the nozzle 26 deforms the pipe 36 is increased until the predetermined compression path, that is the axial relative path that the nozzle 26 travels to the clamping jaw 32, is reached, whereby the clamping surfaces are formed in the desired manner. The pressing force P required for this considerably exceeds the clamping force S that occurs when the nut is tightened using the specified tightening path, taking the thread into account.

In the design of the tool according to Figure 11, a support pin 40 is formed centrally on the nozzle 26 with respect to the axis 31, which protrudes from the base 29a over the front surface 30 of the extension 27 axially in the direction of the pipe 36 and dips into its bore 39 for support. Such support can be particularly advantageous for thin-walled pipes.

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Walterscheid Rohrverbindungstechnik GmbH 08. September 1997 Hauptstraße 150 Hw/kau (0592)

53797 Lohmar P94015DE20

Pipe with a connecting section and pipe connection

List of reference symbols

1 connecting body

2 Nut/union nut 3, 3a Pipe

4 Connection section

5 Front face

6 taper bore

7 Bore

8 Ring shoulder

9 Hole / through hole

10 threads

11 Bore

12 threads

13 Conical surface

14 Curve surface

15 Bore

16 first clamping surface 17, 17a front surface

18 Investment shoulder

19 second clamping surface 20, 21 pipe section

22 Exterior surface

23 Stage 24, 24a, 24b, 24c, 24d Seal 25

26 nozzle/first part tool

27 Approach

28 first conical pressing surface

29 S ac bore

29a Bottom of the blind hole

30 Frontal area

31 Longitudinal axis/tube axis

32 Clamping jaw/second part tool 32a, 32b Clamping jaw halves

33 Bore

34 second conical pressing surface

35 clamping hole

36 Pipe

37 Front face 38

3 9 Bore

40 support pins

41 Area

42 Sealing attachment

43 Sealing element

A Cone angle of the conical bore of the connecting body

B Cone angle of the conical surface of the nut

S clamping force

P Press force

W Tool

X compression

Y pipe projection

D _min . smallest diameter

Claims (11)

Walterscheid Rohrverbindungstechnik GmbH 08 September 1997 Hauptstraße 150 Hw/kau (0592) 53797 Lohmar P94015DE20 Pipe with a connecting section and pipe connection Protection claims 1. Pipe (3) with a connecting section (4) attached to at least one of its two ends by deformation of the pipe end, which has two clamping surfaces (16, 19) designed as conical surfaces and directed against each other, the connecting section (4) being intended for receiving with its first clamping surface (16) in a conical bore (6) designed according to the standard for cutting rings (DIN 386I ₇ as of May 1994, bore shape W) for different pipe outer diameters, this being part of a connecting body (1) or a connecting bore of another body and for supporting with its second clamping surface (19) against a conical surface (13) having a cone angle of 90° and designed as a bore of a union nut (2) matching the connecting body (1) or a union screw matching the connecting bore, which can be pushed over the pipe (3), characterized, that the connecting section (4) is produced by upsetting the pipe (3) in a tool having at least two partial tools (26, 32) that are adjustable relative to one another in the direction of the pipe axis (31) while increasing the pressing force (P) until a predetermined upsetting path (X) is reached, the first partial tool (26) of which has a first conical pressing surface (28) designed in accordance with the conical bore (6) as part of a bore and a stop surface (29a) for the contact of the end face (37) of the pipe (3) and its second part tool (32) has a second conical pressing surface (34) designed as a bore, which has a cone angle of 90°, wherein the free pipe length (L) to be subjected to the upsetting process, with which the pipe projects beyond the smallest diameter (D _min .) of the second conical pressing surface (34) to the stop surface (29a), the length of a sealing cone standardized according to DIN 3865, status May 1994, which results from the difference between the lengths L ₃ and L ₁ for the embodiment A, Figure 1, plus the length of the conical bore resulting from DIN 3861, status May 1994, bore shape W, as well as plus the length of any pipe projection (length Y) provided, which is shorter than the cylindrical bore section adjoining the standardized conical bore, and plus the length the upsetting path (length X), which is a minimum of 6 mm and a maximum of 8.5 mm, and that the relative path which the partial tools (26, 32) have carried out in relation to one another in the direction of the pipe axis (31) during manufacture corresponds to the upsetting path (X), and wherein the upsetting path (X) assumes the maximum value towards the largest pipe outer diameter used. 2. Pipe according to claim 1,
characterized, that a circular cylindrical pipe section (21) is arranged in front of the first clamping surface (16) of the connecting section (4) associated with the conical bore (6). 3. Pipe according to claim 2,
characterized, that a step (23) is provided between the first clamping surface (16) and the outer surface (22) of the pipe section (21). 4. Pipe according to claim 2,
characterized, that a seal (24) is arranged in the free space formed by the step (23) (Figure 4). 5. Pipe according to claim 1,
characterized, that the largest diameter of the first clamping surface (16) of the connecting section (4) ends in an annular contact shoulder (18) (Figure 8). 6. Pipe connection with a pipe (3) which has a connecting section (4) according to the features of claim 1, with a connecting body (1) with a tapered conical bore (6) starting from an end face (5) of the same, to the smallest diameter of which a first circular cylindrical bore (7) which has a bore shape W according to DIN 3861, status May 1994, is connected and with a threaded section (10) attached to the outer surface starting from the first end face (5) and a nut (2) which can be screwed onto the threaded section (10) with a (1) matching threaded bore (11), an adjoining conical surface (13) tapering in the opposite direction to the conical bore (6) of the connecting body (1) and with a bore (15) through which the pipe (3, 3a) is guided. 7. Pipe connection according to claim 6,
characterized, that the conical surface (13) of the nut (2) merges into the bore (15) with a curved surface (14). 8. Pipe connection according to one of claims 6 or 7,
characterized, that a sealing agent (24a) having a liquid or pasty initial state is arranged between the connecting section (4) and/or the pipe sections (20, 21) adjoining it on both sides and the associated areas of the connecting body (1) and the nut (2). 9. Pipe connection according to one of claims 6 to 8,
characterized, that a seal (24b) in the form of a disk is arranged between the end face (17a) of the pipe section (21) arranged in front of the first clamping surface (16) and the ring shoulder (8) of the bore (7) of the connecting body (1). 10. Pipe connection according to one of claims 6 to 9,
characterized, that a seal (24d) is seated on the outside of the connecting section (4) of the pipe (3), which has a sealing projection (4) clamped between the end face (5) of the connecting body (1) and the contact shoulder (18) of the connecting section (4). 11. Pipe connection according to one of claims 6 to 10,
characterized, that a seal (24c) is arranged between the end face (5) of the connecting body (1) and a radially extending surface (41) in the bore of the nut (2).