FR2547631A1 - Method and device for leaktight coupling by clamping using heat for joining two mechanical components together - Google Patents

Abstract

The present invention relates to a device for leaktight coupling by clamping using heat for joining two mechanical components together. This heat clamping device is characterised in that it comprises an intermediate component 14 equipped with any first fastening means 28 interacting with means 26 located on the first component 12b and equipped with second fastening means 17 interacting, when its temperature is above the operating temperature, with means 16 located on the second component 12a, the axial stress in the intermediate component 14 allowing the ends of the first component 12a and of the second component 12b to be clamped against one another, or allowing a seal interposed between the two ends of the first component and of the second component to be squeezed. This invention applies particularly to the leaktight coupling of pipes located in a hostile environment and requiring remote manipulation.

Description

 The present invention relates to a close die and a sealed connection device by thermal clamping to make integral mechanical parts. It applies more particularly to the sealed connection of two mechanical parts such as tubing located in a hostile environment requiring remote handling. It can also be applied to the addition of elements to be mounted on a pipe.

 In known manner, the tight connection of two pipes is carried out using flanges bolted to each of the pipes compressing a seal whose nature is appropriate to the characteristics of the fluid conveyed by the pipes at operating temperatures and pressures.

 In the case of high pressure or high temperatures, as in the case of corrosive fluids, the seals used are metal seals. The pressure necessary to apply to the joint to obtain the seal is very high. This leads to the use of very robust flanges capable of withstanding great clamping forces, generally provided by bolts. In the case where the environment makes dangerous or prohibits direct access to the pipes, the implementation of conventional tightening means requires delicate maneuvers of docking and setting up of bolts, as well as the use of tightening machines of these to the requested couple. In this case, any seizure has very unfortunate consequences.

 The object of the invention is precisely to remedy these drawbacks. It relates to a tight connection device by space-saving thermal clamping and simple implementation, moreover offering great ease and good speed of assembly or disassembly.

 More specifically, the invention relates to a sealed connection process by thermal clamping, which can be carried out remotely, of a first and a second part by an intermediate piece in which the expansion of said intermediate piece is caused. and that its axial contraction allows the ends of the first part and the second part to be clamped against each other or the crushing of a seal interposed between the two ends of the first part and of the second part.

 The invention also relates to a sealed connection device by thermal clamping to make a first part integral with a second part, characterized in that it comprises an intermediate part provided with any first hooking means cooperating with means located on the first part and provided with second hooking means cooperating, when its temperature is higher than the operating temperature, with means located on the second part, a tightening of the three parts being obtained when the temperature of the intermediate part returns to its value normal operation.

 According to a secondary characteristic, the means for attaching the intermediate part to the first part are identical to the means for attaching the intermediate part to the second part.

 According to a particular embodiment, the device in which the first part and the second part are pipes is characterized in that the intermediate part is a sleeve.

 According to another embodiment, the device in which the second part is a tube is characterized in that the first part is a bottom, integral with the intermediate part consisting of a sleeve, closing off the second part.

 According to a secondary characteristic, the device in which the attachment means of each tube consists of a flange located near the end of this tube is characterized in that each means of attachment of the sleeve consists of a collar fixed on the internal face of the sleeve, the position of each collar of the sleeve being such that the sleeve can only be put in place after having been expanded by heating.

 According to another characteristic, the device in which at least one of the flanges of the pipes is cut into sectors is characterized in that each flange of the sleeve cooperating with a flange of a pipe cut into sectors is itself cut into complementary sectors those of the collar of the corresponding tubing.

 According to a parttcfllier mode of. embodiment, the sleeve is made up of two half-shells articulated along an axis parallel to the pipes.

 According to a secondary characteristic, the two half-shells are provided with lage locking means ensuring the closure of the sleeve.

According to a secondary characteristic, the device is characterized in that at least one of the collars of the pipes or of the collars of the sleeve is provided with a thread suitable for the thread of its support allowing it a translational movement along the axis tubing and facilitating the cold positioning of the sleeve on the tubing
According to a secondary characteristic, the axial contraction of the sleeve allows the ends of the tubes to be tightened, thus ensuring conesphere contact or sphere-sphere contact, the latter being particularly well suited to the connection of non-aligned pipes.

 According to a secondary characteristic, the device is characterized in that it further comprises a seal placed between the first part and the second part, this seal being held in position by a fixing means making it integral with one of the tubes.

 According to another characteristic, the device is characterized in that the sleeve is provided with a. integrated heating.

 According to another characteristic, the device is. characterized in. that the sleeve is provided with an insulation.

Other characteristics and advantages of the invention will emerge more clearly from the description which follows, given by way of illustration and not limitation, with reference to the appended figures in which the
- Figure 1 shows a schematic drawing of a longitudinal section of a device according to the invention;
- Figure 2a shows a perspective view of a device for connecting two pipes according to the invention R
- Figure 2b shows a longitudinal section of the device of Figure 2a o
- Figure 3a shows a perspective view of another embodiment of the sleeve;
- Figure 3b shows a longitu ding section of the device of Figure 3e; ;
- Figures da and ab show longitudinal sections of variants of the device comprising threaded flanges é
- Figure 4c shows in longitudinal section a variant of the device allowing the tight connection of two non-aligned parts
- Figure 5 shows in longitudinal section a variant of the device providing the closure of a tube
- Figures Sa and 6b show means for fixing the seal;
Figures 7a and 7b show a device according to the invention, provided with a leak detector;
- Figure 8 -represent a view of a variant of the sealed connection device of two pipes according to the invention.

 FIG. 1 represents a schematic drawing of a sealed connection device by thermal clamping according to the invention. A first part 2 and a second part 4 are made integral by an intermediate part 6. This intermediate part 6 is provided with hooking means 8 cooperating with hooking means 9 located on the first part 2 carrying out the joining of the first part 2 and of the intermediate part 6. This last part further comprises hooking means 10 cooperating when its temperature is higher than its operating temperature, with hooking means II if killed on the second part 4. The attachment between the first part 2 and the intermediate part 6 can be obtained by any means. These attachment means 10 and 11 can for example be of the tenon-mortise type, of the bayonet type, of the screw- nut or any other type. These attachment means 10 and 11 may in particular be identical to the attachment means 8 and 9 between the second part 4 and the intermediate part 6.

 FIGS. 2a and 2b represent a particular embodiment of the device of the invention. The two parts to be joined here are tubes 12a and 12b. The sealed connection device by thermal clamping ensuring the connection of these two pipes 12a and 12b consists of a sleeve 14. The attachment means of the first pipe 12a consists of a flange cut into sectors such as 16. The coupling means of the sleeve 14 cooperating with the coupling means of the tubing 12a also consists of a cut collar.

in sectors such as 17 between which are provided sufficient spaces to ensure the passage of the sectors of the first tube 12a such as the sector 16. One or more of the sectors of the tube 12a or of the sleeve 14 can be equipped with a stop 18. The attachment means of the tubing 12b may be identical to those of the tubing 12e. They can also consist of a complete flange 26, visible in FIG. 2b, in which case the sleeve 14 is integral with the second tube 12b that its. flange 28 is complete or cut into sectors.

 The connection of the two tubes 12a and 12b is done in the following way: a gasket ity 20. is placed at the junction of the two tubes 12a and 12b. If the connection is made by remote handling, and this is the case for example if the environment is dangerous (radioactivity) or if it is hostile (heat)., The seal 20 must be kept in position during the operation # docking of the two tubes 12a and 12b. In the case of FIG. 2b, the tube 12b is provided at its end with a groove 22 which constitutes such a means of holding the seal in position 20. When the embedding of the two tubes 12a and 12b is carried out, the sleeve 14 is placed in position, that is to say it is moved in the tube 12b towards tube 12a direction in an angular position such that the sectors 17 of the rette glue of the sleeve 14 correspond to the empty spaces placed between the sectors 16 of the collar of the tube 12a.

 The sleeve 14 is such that the distance between the internal faces of its flanges is slightly less than the distance between the external faces of the flanges of the pipes 12a and l2b. To tighten the two pipes. .12e and 12b, it is therefore necessary to expand the sleeve 14. This expansion is provided by a heating means 24 which can be any: soldering lamp, induction furnace, electrical resistance or other; the sleeve 14 is brought to a temperature such that the distance between the internal faces of its flanges becomes slightly greater than the distance between the external faces of the flanges of the two pipes 12a and 12b. By rotation of the sleeve 14, the sectors 16 of the tube 12e are then compared with the sectors 17 of the sleeve 14.

 The heating is then stopped. By cooling, li- By cooling, By bre or forced, the sleeve retracts thus creating the force necessary to tighten the seal 2O and to balance the forces acting on the different parts.

 The difference between the distance from the internal faces of the flanges of the sleeve 14 in the clamping position and the distance from the internal faces of these same flanges at rest, represents the crushing of the seal 20 under the pressure necessary to ensure the tightness of the junction of the two tubes 12a and 12b. The distance between the internal faces of the necks ~ lerettes of the sleeve 14 at rest must be chosen carefully so that the tensile stresses generated in the sleeve 14 in the clamping position and the compression stresses generated in the pipes 12a and 12b in clamping position are less than the yield strength of the material of the parts used at the operating temperature and pressure.

 The contact surface between the sleeve 14 on the one hand and the pipes 12a and 12b on the other hand, is small. In the case of pipes working at temperature J a slight thermal imbalance may occur between the sleeve and the pipes 12a and 12b.

The sleeve would then be slightly cooler than the tubes 12a and 12b, which would lead to over-tightening of the seal 20, with the possibility of stresses in the tubes 11a and 12b and in the sleeve 14 exceeding the elastic limit of these materials, this which could lead to a possibility of leakage when the pipes 12a and 12b return to cold.

To overcome this drawback, it suffices to wrap the sleeve 14 with an insulating material 29 of a thickness such that the temperatures of the tube 12a, of the tube 12b and of the sleeve 14 are kept equal.

 FIG. 3ag shows a variant of the embodiment of the sleeve. It consists of two half-shells 34 articulated along a longitudinal axis. This articulated sleeve has the advantage of being put in place and of being dismantled easily. This sleeve can also be made up of three articulated elements which facilitates its installation.

 In general, it can include n articulated elements. The tubes 12a and 12b are each provided with a flange 26. Preferably, the flanges are full and their external face, on which the half-collars # te 28 of the half-shells 34 will rest, will be machined from slightly tapered to facilitate closing of the sleeve. For example, the angle at the top of this cone can be 1750. The internal faces of the half-flanges 28 of the half-shells 34 will be machined in the same way.

 The tight connection by tightening is carried out as follows: the two half-shells 34 are placed on the pipes 12a and 12b when cold. As soon as the temperature of the two half-shells 34 is established, it suffices to bring these two half-shells 34 to contact until contact. The sleeve can be fitted with a locking means 36 making it possible to guarantee its closing. This locking means 36 can be of any known type, and in particular, as shown in the figure, it can consist of two holes drilled in ears 36a fixed to each of the half-shells 34, the closure being guaranteed by the installation of a safety pin 36b.

 FIGS. 4a and 4b show a variant of the device provided with threaded flanges. In Figure 4a, there is shown the longitudinal section of two tubes 12e and 12b. connected by a sleeve 14. The connection between the two pipes 12a and 12b is sealed by the shape of their ends. One can make for example a contact c8ne # sphere as shown in Figures 4a and 4b. This geometry of the ends of the tubes is particularly well suited to the connection of non-aligned tubes. No seal is required. The tube 12b is provided with a collar 16 cooperating with a collar 17 of the sleeve 14.The tube 12a is provided with a collar which can slide on its axis. The collar of this tubing is in fact constituted by a ring 32 provided with an internal thread adapted to a thread produced on the tubing 12a.

 The implementation of the device is carried out as follows: the ring 32 is screwed towards the end of the tube 12a. The sleeve 14 is put in place. This sleeve can be of any type described in the previous figures, in part or in two half-shells, provided with a collar, cooperating with the collar of the tube 12b, complete or cut into sectors. Depending on the case, this sleeve is then secured or not to the tube 12b. The sleeve 14 is placed in the cold position. The threaded ring 32 is then unscrewed, that is to say it is brought into contact with the corresponding flange 28 of the sleeve 14. The heating is then applied to the sleeve 14 until the required temperature is obtained. to unscrew the threaded ring 32 by a known angular value to increase the distance between the external faces of the flanges of the pipes 12a and 12b and thus obtain the desired tightening when returning to temperature equilibrium.

 Figure 4b shows another embodiment of the device comprising a threaded flange. The pipes 12a and 12b are here provided with a continuous flange 26. The sleeve 14 is provided at one of its ends with a continuous flange 28. At its other end, it is provided with a movable flange consisting of a ring 30- sliding along the tube 12a and provided with - 'an external thread- adapted' to a thread made on the internal face of the sleeve 14. The device is implemented in a similar manner to that of the device of the Figure 4a. The sleeve is placed in the cold position and the ring 30 is screwed so that the internal faces of the flanges of the sleeve 14 are in contact with the external faces of the flanges 26 of the pipes 12a and 12b. The sleeve 14 is then heated, which increases the distance between the internal faces of its flanges. A screwing of a known angle of the ring 30 is then carried out so as to reduce the distance between the internal faces of the flanges of the sleeve 14. During the cold return, this sleeve 14 is contracted, which makes the effort tightening the joint.

 FIG. 4c shows a variant of the device of the invention allowing the tight connection by thermal clamping of two non-aligned tubes 12a and 12b, the angle between their respective axes being noted a. A piece 50 ensures the connection of the two tubes by means of sphere contacts. It is provided with elements 51 which come to bear on the spherical end of each tube. The tightening is carried out by the sleeve 14 comprising two parts 14a and 14b, these two parts being able to be screwed into one another. Each part 14a and 14b of the sleeve 14 is terminated at one of its ends by a collar 28a, 28b which comes to bear on the collar 26 of the corresponding tubing.

 The three variants shown in Figures 4a, 4b and 4c have the advantage of not having to pair a sleeve with two tubulu-rese corme this is the case in Figures 2 and 3 where the distance between the internal faces of the flanges of the sleeve is fixed as well as the distance between the external faces of the pipes. The use of threaded flanges makes the device much more flexible. It allows in particular to be able to adjust the tightening pressure of the seal by simply screwing on the flange.

 In Figure 5, there is shown an embodiment of the device providing the obturation of a tube 12. The part providing this obturation consists of two parts o a sleeve 14 and a bottom 5. These two parts are made integral by all known means, such as welding or other. The tubing 12 is provided with a flange cut into sectors such as 16 cooperating with a flange cut into sectors such as 17 of the sleeve 14. The rette glue shown is of flange type by sectors, but could be flanges of the screw ring type such as described in Figures 4a and 4b. The implementation of the device is carried out as follows: the tubing 12 is provided at its end with a seal 20 held in position by a fixing means 23 The part obturation is then attached to this tube 12. The obturation part is then put in place according to the method described in FIG. 2.

 Figures 6a and 6b show different embodiments of the fixing means 38 of the seal 20. In Figure 6a, the fixing of the seal 20 is provided by the tube 12b. This comprises a groove in which the sealing gasket 20 engages. The diameter of the section of this gasket is greater than the depth of the groove so that, when docking the tubing 12a on the tubing 12b, the tubing 12a is in contact with the gasket 20. To ensure the fixing of this etaneheite ioint 20, it is necessary to prevent any movement of tran ion- e9 is to say any movement parallel to the axis of the tubing 12b. This is achieved by an elastic metal seal 38a. Such a seal 20 makes it possible to bring two pipes laterally into contact, - without it being necessary to carry out a translation and a fitting of these pipes.

 FIG. 6b represents a variant of the previous device, where the elastic metal seal 38a is replaced by a threaded ring 38. This ring 38, fixed on the internal surface of the groove of the tube 12b is provided at its end with a blocking protuberance the seal 20. This fixing means 38 can be used when the tubes 12a and 12b are fitted.

 In Figures 7a and 7h, there is shown a device comprising two seals and a leak detector 40. In Figure 7a, the sleeve 14 provides. the connection of the pipes 12a and 12b; this connection is sealed by two seals 20 held in position in the tube 12b by an annular groove. This device is provided with a leak detector 40 connecting the annular groove to the outside allowing a check of the tightness of the connection. Figure 7b shows a variant of Figure 7a. The tubing 12a receives in an annular groove two sampling seals 20 coated with an envelope 42. The leak detector 40 is located on the other tubing 12b.

 FIG. 8 shows another embodiment of the tight connection device by tightening according to the invention in which the tightening part consists of one or more tightening bolts. Each tube 12a and 12b respectively comprises a collar 52a and 52b. The bolts 54 are hollow cylinders traversed by a heating means 56 such as for example a heating element. This heating means can be removable. They can be provided at one of their ends with an elastic means 58 such as a set of belleville washers which makes it possible to limit the forces exerted.

 The clamp connection is as follows. The bolts are heated to a temperature such that their length allows them to engage in the notches 53 of the flanges 52a and 52b of the pipes 12a and 12b. Heating is then stopped and tightening takes place as the bolt retracts as it cools.

 This type of connection has many advantages ç better control of constraints, identical bolt whatever the diameter of the pipes, ease of remote handling.

 The types of seals described are not the only ones that can be used. Other arrangements or types of seals well known to those skilled in the art can be used. In particular, the shape of the sleeve could be such that it is possible to secure the joining of several pieces with this device.

Claims (17)

 1. A method of tight connection by thermal clamping, # which can be performed remotely, of a first and a second part by an intermediate part, characterized in that the said intermediate part expands and its axial contraction allows clamping the ends of the first part and the second part against each other or crushing a seal interposed between the two ends of the first part and the second part.  2 tight connection device by thermal clamping to make a first part (2) integral with a second part (4), according to the method of claim 1, characterized in that it comprises an intermediate part (6) provided with first means any hooking (8) cooperating with means (9) located on the first part (2) and provided with second hooking means (10) cooperating, when its temperature is higher than the operating temperature1 with means (11 ) located on the second part (4), the axial contracture of the intermediate part (6) on cooling allowing the clamping of the ends of the parts (2, 4) or the crushing of a joint interposed between these ends.  3. Device according to claim 2 in which the first part (2) and the second part (4) have substantially the same coefficient of thermal expansion characterized in that the intermediate part has the same coefficient of thermal expansion as said first and second parts .  4. Device according to any one of claims 2 and 3, characterized in that the attachment means (8) of the intermediate part (6) on the first part (2) are identical to the attachment means (10) of the intermediate part (6) on the second part (4).  5. Device according to any one of claims 2 to 4, in which the first part (2) and the second part (4) are pipes (12b and 12a), characterized in that the intermediate part (6) is a sleeve ( 14).  6. Device according to claim 2, wherein the second part (4) is a tube (12), characterized in that the first part (2) is a bottom (5), integral with the intermediate part (6) consisting of 'a sleeve (14), closing the second part (4).  7. Device according to any one of claims 5 and 6 in which the attachment means of each tube (12) consists of a flange (26) located near the end of this tube (12), characterized in that each means of hooking the sleeve (14) consists of a flange (2g) fixed on the internal face of the sleeve (14), the position of each flange (28) of the sleeve being such that the sleeve (14 ) can only be installed after being expanded by heating  8. Device according to claim 7 wherein at least one of the flanges (26) of the pipes is cut into sectors (16), characterized in that each flange (28) of the sleeve cooperating with a flange (26) of a tubing cut into sectors (16) is itself cut into sectors (17) complementary to those of the collar (26) of the corresponding tubing.  9. Device according to claim 5, characterized in that the sleeve (14) consists of at least two elements (34) articulated along an axis parallel to the pipes (12).  10. Device according to claim 9e characterized in that the two half-shells (34) are provided with locking means (36) ensuring the closure of the sleeve (14).  11. Device according to any one of claims 8 to 10, characterized in that at least one of the flanges (26) of the pipes or the flanges (28) of the sleeve is provided with a thread suitable for the thread of its support allowing it a translational movement along the axis of the pipes (12, 12a, 12b).  12. Device according to any one of claims 5 to 11, characterized in that the sealed connection of the two pipes is produced by a cone-sphere contact.  13. Device according to any one of claims 5 to 12, characterized in that a part (50) ensures the sealed connection of the two tubes by means of sphere-sphere contacts.  14. Device according to any one of claims 5 to 13, characterized in that it further comprises one or two seals (20) placed between the first part (2) and the second part (4), this gasket (20) being held in position by a fixing means (22) making it integral with one of the pipes (12, 12a, 12b).  15. Device according to claim 14, characterized in that the sleeve (14) is provided with an integrated heating means (24).  16. Device according to claim 4 in which the first part (12a) and the second part (12b) are pipes, characterized in that the intermediate part consists of a set of thermal bolts (54), provided with a axial heating means (56) which can be integrated.  17. Device according to any one of claims 15 and 16, characterized in that the integrated heating means (24, 56) of the intermediate piece comprises an insulation.