WO2003025447A1

WO2003025447A1 - Pipe assembling connection

Info

Publication number: WO2003025447A1
Application number: PCT/FR2002/003160
Authority: WO
Inventors: Joseph Dugast
Original assignee: Joseph Dugast
Priority date: 2001-09-17
Filing date: 2002-09-17
Publication date: 2003-03-27
Also published as: FR2829827A1

Abstract

The invention concerns a pipe assembling connection, designed in particular for high purity gas distribution lines. Said connection is used for pipes which are each terminated by a tubular end piece (2) including a flange (23) forming a radial support bearing surface for an axially clamping threaded ring of a sealing joint (3) interposed between the connecting ends (22) of said end pieces. It comprises an annular shell (11, 12) with radial clamping effect around said end pieces, including bevel edges (13) co-operating with the matching bevelled surfaces (43) provided on adapting elements (4) urged to be supported on said radial bearing surfaces to cause, when said shell is radially clamped, the two connecting ends (22) to be radially brought together, thereby ensuring a sealing assembly by radial clamping of said sealing joint (3).

Description

PIPE ASSEMBLY CONNECTION

The present invention relates to the field of pipe assembly fittings, in particular that of fittings intended for pipes for high purity gases. Such fittings of the prior art make it possible to ensure a tight connection between two pipes by pinching a seal between the radial end faces of two tubular end pieces terminating said pipes respectively. In this context, the invention aims more particularly to improve the design of the various elements of such fittings, to facilitate the conditions of their cooperation with the two tubular ends of pipes to be connected, to ensure better sealing between the pipes once assembled, while achieving a simple and space-saving assembly, and allowing greater flexibility of use, allowing widespread use of fittings and providing better security at a lower cost.

The present invention is preferably intended for gas pipes equipped with tubular ends such as those commonly found in the field of microelectronics. The tightness of these tubular tips is essential to allow, for example, the creation of a high vacuum in an enclosure in order to deposit thin layers on electronic circuits. In this case, the nozzles must resist very low pressures such as those of secondary voids, for which the residual pressure is approximately between 1 CH Pa (high vacuum) and 10 ^-5 Pa (start of the ultra vacuum). In addition, the tips must also withstand pressures well above 10 ⁵ Pa when a gas is re-entered into the enclosure to return it to atmospheric pressure. The connections of these tubular ends must therefore withstand pressures generally varying between 10 ~ ⁵ and 10 ⁵ Pa and remain perfectly gas tight.

The most common pipe assembly fittings essentially comprise a male part engaged on a nozzle. connecting a first pipe and a female part engaged on a connecting piece of a second pipe, the two pieces mounted on their respective tips cooperating together by a screwing action of one on the other to ensure a watertight blocking of the pipes by means of a seal. To this end, the two parts, generally rings with complementary annular threads, each bear on a radial surface formed by a shoulder on each of the tubular end pieces terminating the pipes to be connected, while being free in rotation and in longitudinal sliding. compared to these tips. Practice shows that one cannot avoid the effect of a torsional effect of the two ends relative to one another when the two parts are screwed to tighten the two ends axially under pressure on the joint d sealing interposed between their end faces. Furthermore, the assembly is awkward because the screwing rings constituting the male part and the female part must have been engaged on the ends of the pipes.

In the path towards a solution to these drawbacks, we find the pipe connection proposed in European patent application EP 89 400 838, by the same applicant. This connection comprises two half-shells external to the end pieces, which close radially by enclosing them in an annular shell and thus clamp the end pieces axially towards one another against the seal without any induced twisting. Their longitudinal locking prevents any movement. A good seal, in particular against gases, can be guaranteed at the connection ends of the tubular end pieces which press on the joint by their end faces.

An important feature for the operation of a connector of this type lies in the conical shape of the connection ends formed by the tubular end pieces terminating the pipes end to end. In addition, an internal chamfer cooperating with the conical shape of the end for connecting the end pieces is provided in each half-shell. When the two half-shells are clamped one on the other, they press radially on the conical parts of the ends of connection of end caps, which slide against the inner chamfers of the half-shells. The connection ends of the end pieces thus approach one another longitudinally (axially) and they compress the seal between them.

This fitting according to the European patent application

EP 89 400 838 however has a significant drawback which hinders its marketing. This drawback lies in the fact that the ends of the pipe ends must have a conical shape, whereas they are commonly produced in cylindrical form with a radial shoulder for supporting the clamping rings by screwing. To solve this problem, the present invention provides a pipe assembly fitting capable of operating by a radial clamping of an annular element causing an axial bringing together of the pipes ends, even when these are standard ends of the trade not having no conical connection ends but a radial shoulder.

It relates to a pipe assembly fitting, in particular for high purity gas pipes, which comprises an annular shell with a clamping effect radially around tubular end pieces terminating pipes end to end and adaptation elements suitable for come to bear on respective shoulders of said end pieces each forming a radial bearing surface for a screw ring in axial clamping of a seal interposed between connection ends of said end pieces, said shell having chamfers cooperating with complementary bevel faces provided on said adaptation elements to produce, during the radial tightening of said shell, an axial approximation of the two connection ends towards each other longitudinally and thus ensure a tight assembly by axial tightening of said joint sealing between said connection ends.

According to a preferred embodiment of the invention, the adaptation elements are composed in particular, on each side of the connector, of adaptation half-rings whose radius is close to that of the corresponding tubular end-piece to be placed against the shoulders of the connection ends in order to center the elements of the outer shell with a radial tightening effect at the same time as a longitudinal tightening of the end-pieces along their axis.

Advantageously, the outer annular shell is made up of two half-shells which can be joined together, in particular by bolts or screws, along the generatrices of the pipe ends, internally providing a chamber sufficient to accommodate the ends of connection of the ends between the chamfers. annular vis-à-vis which determine the longitudinal approximation of the tips when said half-shells are tightened radially towards each other. According to an advantageous embodiment of the invention, the two half-shells of the connector are mounted articulated on a hinge or the like, which makes it easier to put the shell in place.

The adaptation elements are advantageously removable and / or interchangeable. In this way, provision can be made to use the same radial clamping shell device with different existing pipe end pieces, each time choosing suitable adaptation elements having varying diameters and thicknesses.

Still other characteristics of the invention take advantage of the presence of these adaptation elements, advantageously each made in several annular sectors (in particular each by two half-rings), to improve the efficiency and the precision of the operation of the outer shell, advantageously also made up of several elements in annular sectors, in particular of two half-shells, in that the radial tightening causes an axial tightening compressing the intermediate joint, thanks to the cooperating chamfers. It is thus, in particular, that it is advantageous that the adaptation elements are free to slide radially on the shoulders of the end pieces and axially on their outer periphery upstream of the ends. compressing the joint. Their mobility allows them to play a role of centering the shell elements towards the joint area.

Although not limited to, it is preferably in combination with these latter features that we will, most often, benefit from constituting the outer shell by two half-shells joining together according to a diameter of the overall assembly, which are articulated l '' in relation to each other, and which are put in place by making them step over the pipe ends in the end-to-end position, before bringing them towards each other in radial tightening, which is why they are advantageously fitted with assembly screws or bolts connecting them.

The adaptation elements can advantageously be fixed, or more exactly linked in mobile mounting along the chamfers of the radial clamping elements (the elements of the outer shell), for example by means of rivets guided in a lumen formed in the latter. According to this embodiment, the light is advantageously sized to allow the displacement of the adaptation elements along the chamfers of the clamping elements.

According to other features of the invention, means are provided to ensure correct positioning of the seal during assembly of the fitting while keeping it correctly centered on the axis of the end pieces. Thus, for example, a groove can be formed in the center of the inner part of the outer shell elements to accommodate the seal, which has the advantageous result of facilitating the fitting of the fitting and improving its effectiveness in tight compression of the joint.

According to an advantageous embodiment which will be more fully illustrated below, the connector according to the invention comprises a retaining part for the seal which is inserted inside the elements of the external radial tightening shell, preferably at their center. , this joint holding part comprising a housing for receiving it. Such a joint retaining part is preferably in the form of a half-ring in which is formed a groove for receiving the joint whose width is close to the peripheral thickness of the joint. According to an alternative embodiment of the connector according to the invention, the joint holding part comprises elements allowing it to hang on the connection end of one of the two end pieces. Such hooking elements consist in particular of flexible tongues.

By its different characteristics, as they have been succinctly defined above or that they will be described and illustrated below, and such that they can be advantageously used in industrial practice, separately or in each of their combinations technically operational, the invention makes it possible in particular to connect the tubular ends currently marketed, whatever the model, without the need to machine them. It also makes it possible to improve the safety and the efficiency of the fittings in terms of their sealing performance.

The assembly fittings according to the invention have many other advantages. Among these, it should be noted that they can be dismantled up to a hundred times. They also have the advantage of requiring only a short set-up time, and a low qualification of the fitters. Furthermore, it is possible in the event of loss or deterioration to replace only one piece of the fitting, and not the whole of the latter. Finally, the connector according to the invention can easily be made of a material compatible with the fluids or gases flowing in the pipes. Thus, it does not interfere in the circulation of the fluid and it does not pollute the pure gas circulating in the pipe fittings.

The assembly fittings according to the present invention ensure good sealing of the pipe system and withstand both very low pressures such as those of secondary voids, and high pressures. In their preferred embodiments, the assembly fittings according to the present invention withstand pressures between 10-10 bars (1 0 ~ 5 Pa) and 350 bars (350.10 $ Pa). The invention will now be more fully described in the context of preferred characteristics and their advantages, with reference to FIGS. 1 to 9 in which:

- Figure 1 shows a partial longitudinal sectional view of half-shells constituting the radial clamping shell elements in the connector, the latter ensuring the assembly of two tubular end pieces which are shown one (above the 'X axis) in longitudinal section, the other in side view (below the X axis); - Figure 2 illustrates an exploded view in longitudinal section of the elements of the connector of Figure 1 located above the axis

X;

- Figure 3 shows a sectional view of a half-shell according to a secondary embodiment of the invention, as well as a sectional view of part of a joint;

- Figure 4 shows a sectional view of a half-shell according to another secondary embodiment of the invention, as well as a sectional view of a part for holding a joint according to a first embodiment , and a sectional view of part of a joint;

- Figure 5 shows a perspective view of a preferred embodiment of a seal holding part, and a seal to be inserted therein;

- Figure 6 shows a side view of the joint holding part shown in Figure 5, inserted on the end of a first tubular nozzle, as well as a second tubular nozzle aligned in the axis of the first nozzle including l the end comes into contact with the seal to be inserted in the seal holding part; Figure 7 shows a second alternative embodiment of the connector according to the invention in longitudinal section;

- Figure 8 shows a third alternative embodiment of the joint connection according to the invention in longitudinal section;

- Figure 9 illustrates an embodiment of the connector according to the invention in side view; - And Figure 1 0 is a sectional view of the connector shown in Figure 9.

As shown in FIG. 1, the pipe assembly connector according to the invention chosen for example ensures the assembly of two tubular ends of pipes end to end. As is common, each tubular end piece 2 has a connection end 22 of generally cylindrical shape, and of larger diameter than that of the pipe terminated by the end piece 2. In this way, the connection end is projecting relative to the periphery of the current part of the pipeline. More specifically, it forms a shoulder which constitutes a bearing surface on which abuts an assembly ring when a conventional assembly mode is used by two rings screwing one on the other around the end pieces of pipes in sliding axially thereon. This shoulder 23 forms a right angle between the cylindrical periphery of the end piece and a part of the connection end of the end piece which is radially projecting, as can be seen in particular in FIG. 2.

Finally, the connection end 22 has a radial end face 21 forming an annular bead of bi-conical section towards a blunt tip coming into contact with the seal 3 interposed between the two end-to-end end pieces. The rounded conical shape of the terminal face 21 ensures a precise correspondence with the surface of the seal 3 (FIG. 2), and by that very fact a better seal.

As can be seen in Figure 1, the pipe fitting comprises, in addition to the seal 3, components of an outer annular shell 1 which acts in radial (or transverse) tightening to tighten the two ends axially (or longitudinally) towards each other, as well as adaptation elements 4. The latter match on one face the internal shape of the radial clamping elements, and on another the external shape of the tubular end pieces 2, just in upstream of the shoulders 23. According to a first embodiment of the connector according to the invention, it also includes a part 6 for holding the seal 3, shown in FIGS. 1, 5 and 6.

In the example illustrating the preferred characteristics of the invention, the outer annular shell 1 consists of two half-shells 1 1 and 12, shown in particular in FIG. 1. Radially close to each other, they serve to enclose the assembly constituted by the tubular end pieces 2, the adaptation elements 4, the seal 3 and the seal holding part 6, while compressing the latter thanks to an axial approximation of the end faces of the connection ends of the end pieces towards one another.

Each of the two half-shells 1 1, 12 provides inside a chamber of sufficient volume to admit without touching the connection ends 22 of the end pieces 2 between two chamfers 1 3. The two chamfers 13 are shaped to cooperate with faces in bevel 43 that includes the adaptation elements 4. This makes it possible to center said shell on the axis of the end pieces 2, at the same time as a longitudinal tightening of the end pieces 2 along the axis.

As shown in FIG. 10, each half-shell is pierced with two lateral orifices 14 where two assembly screws 7 appearing appearing in FIG. 9. The assembly screws 7 pass through a first half-shell 1 1 by a orifice 14. Each is screwed into a threaded orifice 14 corresponding to the second half-shell 12 while it is in abutment by its head against the first. The two half-shells then approach each other, until they meet along a diametrical plane of the assembly. In the context of the embodiment considered here, the screws 7 are non-removable screws.

Advantageously, the two half-shells are mounted in an articulated manner with each other, each on a connecting piece 8 which connects them. For this, openings 15, visible in Figures 9 and 10, are formed in each half-shell parallel to the axis of the connector. One of them is cylindrical, while the other elongates into a light 20 allowing a translation perpendicular to the axis of articulation, when the half-shells approach them one from the other.

The connecting piece 8, shown in Figure 9, is designed to allow the two half-shells 1 1 and 12 to be connected in order to facilitate the fitting of the fitting. The connecting piece 8 is advantageously in the form of a clamp with two flaps connected to each other by an intermediate piece which envelops part of the external surface of each of the half-shells. Advantageously, the part of the external surface which is enveloped by the part has in particular the two orifices 15.

In order to allow the attachment of the half-shells to the connection piece, two openings 81, of cylindrical shape, are formed in each of the two flaps of the connection piece. Each of the half-shells 1 1, 12 is advantageously mounted articulated on the connecting piece 8 by means, for example, of rivets, not shown in the figures, passing through the opening 15 made in the half-shells and one of the openings 81 of the connecting piece 8. The axes of the rivets constitute the axes of articulation of the half-shells on the connecting piece 8.

As explained above, the connector according to the invention comprises adaptation elements 4 from the internal shape of the clamping elements 1 to the external shape of the connection ends of the tubular end pieces 2.

More precisely, and as is notably represented in FIGS. 1 and 2, the adaptation elements 4 associate the shape of the chamfers 13 which the half-shells 1 1 and 12 have with the shape of the shoulders which the ends of the connecting pieces have. tubular 2. The adaptation elements 4 are made to be placed against the shoulder 23 of said connection end 22, between said connection end 22 and one of the half-shells 1 1 and 12. As can be seen in FIGS. 1 and 2, the adaptation elements are adaptation half-rings 4 having a bevelled face 43 which comes to cooperate with one of the chamfers that a half-shell comprises. This allows, when the half-shells 1 1 and 12 are tightened together and they are radially close to one another, at the same time bringing the end faces 21 of the two tubular ends one of the 'other. In this way, a seal located between two connection ends is perfectly pressed between the two end faces 21 when the two half-shells 1 1 and 12 are screwed, and the seal is thus well ensured between the two faces. connection ends.

In order to facilitate the mounting of the various elements constituting the connection, it is possible to provide, as in the present case, a device for holding each adaptation half-ring 4 inside the half-shell 1 1 or 12 to which it is associated, so that the bevelled face 43 of each adaptation half-ring 4 remains well opposite the chamfer 1 3.

As illustrated in FIG. 1, this holding device comprises a rivet 41 which is placed in sliding connection with a through lumen 42 formed in each half-shell 11, 12.

The head of the rivet 41 is disposed outside the half-shell 1 1,

12 and its end is fixed to the adaptation half-ring 4.

The width of the lights 42 is such that the rivets 41 can slide inside the lights 42 during the tightening of the two half-shells. In fact, as explained above, the bevelled face 43 of the adaptation half-rings 4 is intended to operate with a chamfer 13 of each of the half-shells. When the two half-shells are tightened, the chamfers 1 3 guide the adapter rings towards the center of the half-shells by sliding the bevel face 43 on the chamfer 13, thus pushing the two connection ends of the tubular ends to compress against the seal. there is therefore movement of the adaptation half-rings 4 towards the center of the half-shells, and consequently movement of the rivets 41 towards the center of the half-shells 1 1, 12. The width of the openings is such that the rivets can therefore move there without hampering the tightening of the two half-shells 1 1, 12 with one another.

For the same purpose of facilitating the mounting of the connector according to the invention, and according to an embodiment shown in FIGS. 1, 5 and 6, the connector includes a joint holding part 6 which is in the form of a bowl. annular (FIG. 5), the bottom of which has been hollowed out so as to form a peripheral internal shoulder 62. The retaining part 6 also includes a fixing system, constituted by flexible tongues 61 formed in its lateral periphery and uniformly distributed around this one. The flexible tongues 61 protrude towards the inside of the holding part 6.

The flexible tabs 61 have a dual role. They allow on the one hand to fix the joint holding part 6 on the end of a nozzle 2, as shown in FIG. 6, and on the other hand to hold the joint 3 against the peripheral internal shoulder 62. For To do this, the diameter of the seal holding part 6 is slightly greater than the diameter of the seal 3.

As shown in Figure 5, the seal 3 is a conventional seal in itself. It is made up of a metal washer. The outside diameter of the seal corresponds precisely to that of the ends 22 of the tubular ends of cylindrical shape. The internal diameter of a central orifice of the seal 3 is such that it corresponds practically to the diameter of the interior pipe of the tubular end pieces 2, at least when the seal is actually compressed between the two connection ends 22.

It will be noted that the connector according to the invention could have other means for holding the joint, equivalent to the preceding ones, which, like them, would ensure that the joint remains correctly in place, centered on the axis of the end pieces to be connected.

According to an alternative embodiment of the invention illustrated in Figure 3, a groove 31 is formed in the center of the inner part of the two half-shells 1 1 ', over their entire periphery, to allow the establishment of the seal 3 in the center of each of the half-shells 1 1 '. Also, the width of the groove 31 is close to the thickness of the joint 3 so that it can be inserted therein and so that it can be kept perpendicular to the axis of the end pieces during assembly.

According to another alternative embodiment of the invention, the connector shown in FIG. 4 comprises a joint retaining part 5 which is in the form of a half-ring in which is formed a groove 52 whose width is close to the peripheral thickness of the joint 3. In order to receive the joint holding part 5, half-shells 1 1 "of the connector according to the invention have a central groove 51, formed all along the interior of each half shell, and the width of the groove 51 is close to that of the joint retaining part 5.

Furthermore, a conduit is formed through one of the half-shells 1 1 or 12, from the internal chamber to the outside, for the detection of possible gas leaks, but this conduit does not appear in the figures for a reason for clarity of these.

We are now going to focus on the mounting of this assembly connector according to the embodiment which has just been described, the connector comprising the part 6 for holding the joint in FIGS. 5 and 6.

First of all, as shown in FIG. 5, the seal 3 is inserted in the seal holding part 6. Then, as can be seen in FIG. 6, the seal holding part 6 is placed on the end 22 of a tubular end piece 2, by introducing said end 22 inside the holding part 6, the flexible tongues 61 ensuring the fixing of the joint holding part 6 on the connection end 22. From in this way, the conical bead end face 21 of the connection end 22 comes into contact with the seal 3.

Then, place in the two half-shells 1 1 and 12 four adaptation half-rings 4 (two in each, respectively on each side), by affixing the bevelled face 43 of each adaptation half-ring 4 against each of the two chamfers 13 of each half-shell 1 1, 12. Then, they are fixed with the rivets 41 to hold them in place.

Each half-shell is then mounted on the articulation piece 8 by inserting a rivet in the opening 15 of the half-shells 11, 12 and in the opening 81 of the articulation piece 8. Then, the end piece provided with the gasket 3 and the gasket retaining part 6 is placed in the half-shell 12, placing the shoulder 23 of the connection end 22 against one of the adaptation half-rings 4.

Then, a second end piece is placed inside the half-shell 12 in such a way that the end face 21 of the end of this second end piece is brought against the seal 3, on the bottom side of the part. holding the seal 6, and in such a way that the shoulder of the end of the second end piece is disposed against the second adaptation half-ring. The two end pieces are then aligned along the same axis X. Finally, the half-shell 12 is placed on the half-shell 1 1, and the two half-shells 1 1, 12 are clamped one against the other with the assembly screws 7 placed in the lateral orifice 14 of each of the half-shells 1 1, 12.

When the two half-shells 1 1, 12 are screwed towards each other, the chamfers 13 of the two half-shells 1 1, 12 exert pressure on the bevelled faces 43 of the adaptation half-rings. With this pressure, the bevelled face 43 of each half-ring 4 slides on the chamfer 13 of the half-shells 1 1, 12 towards the center of the latter. The adaptation half-rings 4 then exert pressure on the shoulders of the connection ends 22, then compressing the end face 21 of each connection end 22 against the seal 3.

It will be clearly understood from the foregoing description that it only describes an embodiment of the connector according to the invention. I t is indeed possible to find adaptation elements having a form other than that of a half-ring 4. FIG. 7 illustrates another embodiment of adaptation elements 4 ′ of the internal shape of half-shells 16 and 17 to the shape of the connection ends of the tubular ends 2 of pipe.

The half-shells 16 and 17 have a shape different from that of the half-shells 1 1 and 12 shown in FIGS. 1. The half-shells 16 and 17 each have two bent arms, the shape of each of which is defined by a bearing and an inclined plane, while the half-shells 1 1 and 12 each have two arms, the shape of which is defined only by a inclined plane. Furthermore, the half-shells 16 and 17 each have a protuberance 10 on each of its bent arms, at the end of the bearing of each of them.

According to this embodiment illustrated in FIG. 7, the adaptation elements 4 ′ comprise a main cavity 44 forming a housing for receiving one of the bent arms of a half-shell 16 or 17. The main cavity 44 comprises at least one bevel face 43 'coming to cooperate with the chamfer 13' that each bent arm of each of the half-shells 16 and 1 7 has. Furthermore, each adaptation element 4 'is produced in such a way that it is retained at the half-shell by the protuberance 10. To do this, a housing having the imprint of the protrusion 10 is produced in the cavity 44, as shown in FIG. 7.

For better retention of the adaptation elements on the bent arm of each of the half-shells 16 and 17, the adaptation elements 4 ′ are retained there by rivets 46 passing through them. As for the rivets 41 retaining the adaptation elements 4 (represented in FIGS. 1 and 2) to the half-shells 1 1 and 12, the rivets pass through a lumen formed in the half-shells 1 6 and 17 of larger dimensions than those of the rivet, so that it can move freely when tightening the two half-shells together.

FIG. 8 shows yet another embodiment of adaptation elements 4 "of the shoulders 23 of the ends of connection 22 to the chamfers presented by the bent arms of two half-shells 18 and 1 9. The two half-shells 18 and 19 have no protuberance for holding the adaptation elements 4 "there. As for the adaptation elements 4 ", they comprise a cavity comprising at least one bevelled face 43" coming to cooperate with the chamfer 13 "that each bent arm of each of the half-shells 18 and 1 9 has. The adaptation elements 4" are held at half shells 18 and 19 by means of rivets 46 'passing through them; and the dimensions of the lumen are larger than those of the rivet, so that the rivet moves there freely when the two half-shells are tightened together.

The foregoing description clearly explains how the invention achieves the objectives it has set for itself. In particular, it is understood that the adaptation half-rings 4 play an important role in the tightness of the assembly fitting, since their shape complementary to that of an inner part of the half-shells 1 1, 12 ultimately allows compressing the end faces 21 of the connection ends 22 of the end pieces 2 against the seal 3. In addition, the seal holding part 6 allows the fitting to be mounted quickly and easily, since it is sufficient to insert the seal 3 in the latter and fix everything on the end of a nozzle. The seal 3 is then directly centered on the axis of the nozzle.

However, it follows from the above that the invention is not limited to the modes of implementation which have been specifically described and shown in the figures. In particular, it should be understood that more than two half-shells could be used, and in an equivalent manner, to constitute a complete annular shell enclosing the assembly, and that likewise, the adaptation rings could be divided into more than two annular sectors.

Claims

1. Pipe assembly fitting, in particular for high purity gas pipes, characterized in that it comprises an annular outer shell (1 1 -12), with clamping effect radially around tubular ends (2) terminating end-to-end pipes, and adaptation elements (4) capable of coming to bear on respective shoulders (23) of said end pieces forming radial bearing surfaces for screw rings in axial clamping of a gasket sealing (3) interposed between connection ends (22) of said end pieces, said shell having chamfers (13) cooperating with complementary bevel faces (43) formed on said adaptation elements to produce, during tightening radial of said shell, an axial bringing together of the two connection ends (22) towards one another and thus ensuring a tight assembly by axial tightening of said seal (3) between said ends s connection (22).

2. Connection according to claim 1, characterized in that said adaptation elements consist, on each side of the connection, of adaptation half-rings (4), the radius of which is close to that of said tubular end piece (2) corresponding and which are placed against said shoulders (23) in order to produce a centering of elements constituting said outer shell with a radial tightening effect at the same time as a longitudinal tightening of said end pieces (2) along their axis.

3. Connection according to claim 1 or 2, characterized in that said outer shell comprises two half-shells (1 1, 12), which can be joined together along generatrices of said end pieces, internally providing a sufficient chamber to accommodate said connection ends (22) of said end pieces (2) between the annular chamfers (13) facing each other which determine the longitudinal approximation of said end pieces (2) when said half-shells are tightened radially towards one another.

4. Connection according to claim 3, characterized in that the two half-shells (1 1, 12) are mounted articulated on a hinge or the like (8).

5. A connector according to any one of claims 1 to 4, characterized in that said outer shell comprises two half-shells (1 1, 12) meeting at a diameter which are equipped with bolts or screws (7) assembly to bring them towards one another in radial clamping around said end pieces.

6. Connection according to any one of the preceding claims, characterized in that said adaptation elements (4) are mounted movable along said chamfers (13) of said outer shell (1) and free to slide radially on said shoulders ( 23) end caps (2) and axially on their outer periphery upstream of the connection ends (22) compressing the seal (3).

7. Connection according to any one of the preceding claims, characterized in that it comprises means (31, 5-

6) to ensure the positioning of the seal (3) during assembly of the fitting while keeping it correctly centered on the axis of said end pieces (2).

8. A connector according to claim 7, characterized in that it comprises a part (5,6) for holding said seal (3) which is inserted inside the elements of said external radial tightening shell (1), said part (5, 6) advantageously being inserted in the center of said shell elements and comprising a housing for receiving said seal.

9. A connector according to claim 8, characterized in that said retaining part (5) of seal (3) is in the form of a half-ring in which is formed a groove (52) for receiving said seal ( 3) whose width is close to the peripheral thickness of said seal (3).

10. Pipe assembly connector according to claim 8, characterized in that said retaining piece (6) of joint (3) comprises elements for hooking to said connection end of one of the two end pieces (2) , said fastening elements being in particular made up of flexible tongues (6).