Clamping system for connecting tubing, including collars and seals

Abstract

The clamping system is used to connect a first tube and a second tube, with opposing ends of the tubes having support surfaces that protrude relative to the tubes' cylindrical outer surfaces. The clamping system includes a clampable collar (10) and a seal (20). The collar includes a belt (12) whose inner periphery defines a recess that can cooperate with the support surface of the tube, and the support surface can be inserted into the recess. The seal (20) is supported by the collar in its unclamped state and includes an annular sealing portion (21), which includes a metal washer (22) and a non-metallic washer (24) secured to the metal washer. The metal washer may have support lugs (30, 32) that support the washer relative to the collar.

Description

[Technical Field]

[0001] Technical Field The present disclosure relates to a clamping system for connecting a first tube and a second tube, wherein opposing ends of the tubes have support surfaces that protrude relative to the cylindrical outer surface of the tubes, the system having a collar and a seal, and the collar can be tightened around the support surfaces of the tubes. [Background technology]

[0002] prior art EP 1451498 (Patent Document 1), EP 2598785 (Patent Document 2), and EP 3232107 (Patent Document 3) disclose a clamping system having a collar with a belt that can be tightened by reducing its diameter and a seal pre-attached to the collar. More specifically, the system includes a washer with a closed annular portion that forms the seal and a lug connecting the seal to the collar. The closed annular seal is initially held relative to the collar's belt, thereby creating a space between the seal and the inner circumference of the belt and allowing the end of the tube to engage between the seal and the belt. The inner tube is then brought into contact with the seal. This device serves as a bearing for the clamping collar, which is particularly suitable for clamping two tubes that fit together and have radially protruding surfaces, including recesses that can accommodate these radially protruding surfaces, and the closed annular seal itself has a shape that matches these protruding surfaces.

[0003] In particular, such seals, as well as the belts of the collar, may be made of metal of the stainless steel type.

[0004] U.S. Patent No. 4,185,858 also discloses a clamping system that includes a clamping collar and a two-part seal. The seal includes a metal support washer and a compressible bead made of silicone rubber that is bonded to the washer. Only the bead functions to ensure sealing, while the washer acts only as a support for the bead. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] European Patent No. 1451498 [Patent Document 2] European Patent No. 2598785 [Patent Document 3] European Patent No. 3232107 [Patent Document 4] U.S. Patent No. 4,185,858 Summary of the Invention

[0006] Disclosure of the Invention In some applications, particularly in the automotive sector, and especially in the exhaust lines of combustion engines, there is a need to improve the above-mentioned types of seals so that they can withstand increasingly higher temperatures. Indeed, as technology advances, it is possible that the temperatures of the tubes, and especially those parts that come into contact with the seals, can reach several hundred degrees, even exceeding 900°C. However, at such temperatures combined with high clamping stresses, the metallic material of the seals can lose some of its elasticity necessary to maintain a seal. While thicker metal seals may be able to ensure sealing at high temperatures and high clamping stresses, such seals are expensive, heavy, and insufficient in cold weather. Therefore, if a clamping system is used to connect two tubes that form part of the exhaust line of a vehicle's heat engine, such a thick seal would be completely ineffective for starting the engine. [Problem to be solved by the invention]

[0007] The present disclosure aims to at least substantially overcome the above-mentioned drawbacks. [Means for solving the problem]

[0008] Accordingly, the present disclosure relates to a clamping system for connecting first and second tubes, wherein opposing ends of the tubes have support surfaces that protrude relative to the cylindrical outer surfaces of the tubes, the system including a tightenable collar and a seal, the collar including a belt that can cooperate with the support surfaces by its inner periphery defining a recess that can be inserted into the recess, the seal being supported in the latter's unfastened state by the collar and including an annular sealing portion, the annular sealing portion including a metallic washer and a non-metallic washer fixed to the metallic washer, the non-metallic washer being formed from a composite material.

[0009] Optionally, the metal washer has support lugs that support the metal washer and the non-metallic washer relative to the collar.

[0010] Optionally, at least some of the support lugs are integrally formed with metal washers.

[0011] Optionally, the metal washer has a stamped frusto-conical surface and the non-metallic washer is formed into a planar ring and deformed to fit the frusto-conical shape of the frusto-conical surface.

[0012] Optionally, a non-metallic washer is glued to the metallic washer.

[0013] Optionally, the metal washer has retention lugs that cooperate with the non-metallic washer to hold the non-metallic washer relative to the metal washer.

[0014] Optionally, a retaining lug is cut into the metal washer.

[0015] Optionally, the non-metallic washer is formed from a mica-based material.

[0016] Optionally, the non-metallic washer comprises mineral particles, particularly mica or graphite, and a binder.

[0017] Optionally, the non-metallic washer includes a reinforcement, particularly a metal reinforcement.

[0018] Optionally, the metal washer has an annular ridge on a first surface of the metal washer, and a non-metallic washer is disposed opposite the first surface.

[0019] Optionally, the non-metallic washer has an annular ridge on a first surface of the non-metallic washer, and the first surface of the metallic washer and the first surface of the non-metallic washer are positioned opposite each other, whereby the annular ridges are in contact.

[0020] Optionally, the non-metallic washer also has an annular ridge on its second surface, and the annular ridges of the non-metallic washer optionally together bound an annular space.

[0021] Optionally, the annular sealing portion further includes an additional non-metallic washer secured to the metal washer, whereby the metal washer is located between the non-metallic washer and the additional non-metallic washer.

[0022] According to the disclosure, the seal of the clamping system thus includes two washers, one metallic and the other non-metallic, secured together. The pair of these two washers can be held relative to the collar using an appropriate seal configuration. The parts required for sealing, i.e., the annular sealing portion including the metallic washer and the non-metallic washer, can be easily shaped to meet the sealing requirements, taking into account the clamping stress and the temperature level of concern. This annular sealing portion is intended to be placed between the opposing surfaces of the tubes connected using the clamping system and to be sandwiched and clamped between these surfaces during the tightening of the collar. In particular, the non-metallic washer may include a material, particularly a mica-based material, adapted to retain elastic deformation at high temperatures and contribute to sealing over a wide temperature and stress range. The seal can be lightweight, with the metallic washer portion providing its strength and mechanical resistance, and the non-metallic portion contributing to its effectiveness, particularly at high temperatures and pressures. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a perspective view of a clamping system according to the present disclosure, viewed from a first side. [Figure 2] FIG. 2 is a perspective view of the system depicted in FIG. 1, seen from another side. [Figure 3] FIG. 1 is an exploded perspective view showing the different components that make up the clamping system, shown separately, as well as the ends of two tubes that are assembled using this system. [Figure 4] 1, showing, on the one hand, the clamping system according to the disclosure and, on the other hand, the ends of two tubes to be assembled using this clamping system; [Figure 5] FIG. 2 is an enlarged view of detail V in FIG. [Figure 6] FIG. 3 is an enlarged view of detail VI in FIG. 2. [Figure 7] FIG. 7 is an enlarged view of detail VII in FIG. [Figure 8]5 is a partial axial cross-sectional view similar to FIG. 4 of an alternative embodiment. [Figure 9] FIG. 10 is a partial perspective view showing one variation of the seal. DETAILED DESCRIPTION OF THE INVENTION

[0024] Description of Aspects 1 shows a clamping collar 10 including a belt 12 with radially raised ends to form clamping lugs 12A and 12B, respectively. To tighten the collar, the diameter of the belt is reduced by cooperation with clamping lugs 12A and 12B of a clamping screw 14. The shank 14B of the screw passes through a hole in the clamping lug, its head 14A cooperating with lug 12A, and at its opposite end is a nut 14C which cooperates with lug 12B, in this case by means of a spacer 14D.

[0025] Belt 12 has an internal recess 15 (better seen in FIG. 4) located between its two sides, 12C and 12D. Seal 20 is located inside the belt. As best seen in FIG. 4, a clamping system is used to connect two tubes 1 and 2, each with a support surface 1A or 2A at its end. To connect the tubes, their ends are brought together axially until they enter recess 15, and the belt diameter is reduced so that sides 12C and 12D press against support surfaces 1A and 2A. In this case, support surfaces 1A and 2A are formed on radial flanges on the ends of tubes 1 and 2. As shown, seal 20 is located within a collar. For the connection of tubes 1 and 2, front faces 1'A and 2'A of the ends of tubes 1A and 2A are located on either side of an annular sealing portion 21 of seal 20.

[0026] Within the meaning of this disclosure, the forward direction for tube 1 or 2 is the direction toward the other tube 2 or 1 when their ends are brought together to assemble the tubes. Thus, the support surfaces 1A and 2A are formed on the undersides of the radial flanges that the tube ends have. The reverse direction is obviously the opposite direction. For components, the inward direction is the direction toward axis A. The outward direction is the opposite.

[0027] The annular sealing portion includes a metal washer 22 and a non-metallic washer 24 secured to the metal washer. In this case, as can be seen by considering Figures 1, 2, and 3 together, the annular sealing portion includes metal washer 22, non-metallic washer 24 disposed on a first side of the metal washer, and non-metallic washer 26 disposed on the other side of the metal washer. Thus, metal washer 22 is sandwiched between non-metallic washers 24 and 26.

[0028] For example, the metal washer 22 can be made of the same metal as the belt 12, such as stainless steel. The non-metallic washers 24, 26 can be made of composite materials. They can be made of mica-based materials. The non-metallic washers can include mineral particles, particularly mica or graphite, and a binder. The non-metallic washers can include a reinforcement, particularly a metal reinforcement, supporting a non-metallic material, particularly a mica- or graphite-based composite material. For example, the reinforcement can be a fine wire mesh.

[0029] The designation that a washer 24 or 26 is "non-metallic" means that the washer does not contain metal, or if it does contain metal, e.g., a metal reinforcement, the metal represents only a small portion of the washer by mass, e.g., the mass of the metal does not represent more than 40% of the washer's mass, and in particular no more than 20 or 30%.

[0030] The non-metallic washers 24 and 26 are supported by the metal washer 22. Thus, as can be seen from Figures 1-3, the metal washer 22 has support lugs that support the metal and non-metallic washers relative to the collar 10. The seal is therefore pre-installed in the belt, i.e., the collar has the seal before it is placed on the tube and tightened, so that the collar and seal can be handled together.

[0031] Furthermore, the metal washer may also have support lugs that are used to pre-mount the collar with the washer onto one of the tubes to be assembled. Thus, the assembly formed by the collar and seal can be placed on one end of the tube and remain in the same position at this end before placing the other end of the tube and tightening the collar. The same lugs may have a dual function, being used to pre-mount the seal in the belt and to pre-mount the assembly formed by the collar and seal at one end of the tube. These support lugs are supported by the outer periphery of the metal washer 22 (away from the axis A of the belt).

[0032] In this case, three different types of lugs have been represented. As can be seen better in Figures 7 and 9, the support lugs 30 have hook-shaped curved ends 30A so that they can be hooked onto the edge 13 of the side 12C of the belt 12. Between the outer periphery 22' of the metal washer 22 and the area of ​​connection to this hook 30A, these lugs 30 have an axial segment 30B that extends substantially axially, i.e., substantially parallel to the axis A. As can be seen better in Figure 7, this axial segment 30B has, on the one hand, a hooking tab 30C cut into the axial segment 30B and that is radially folded by extending towards its free end in the direction from the hook 30A to the outer periphery 22' of the metal washer 22. This tab 30C is used to grip the washer on the support surface 1A of the tube 1 and to hold a collar previously attached to the end of this tube. It will be appreciated that the orientation of these tabs 30C prevents the tube from being released from the washer in a rearward direction relative to the tube 1, according to arrow R1 shown in FIG.

[0033] Furthermore, the support lug 30 has wings 30D that fold radially outward from the longitudinal edges of the axial segments 30B, i.e., away from the axis A. These wings 30D further have retention edges 30D' that are oriented toward the inner surface of the hook 30A, and thus toward the inner surface of the side 12C of the belt 12, when the seal is pre-installed in the washer. These retention edges 30D' are spaced apart from the inner surface of the hook 30A. The edge 13 of the side 12C is housed in the space, i.e., located between the hook 30A and the retention edges 30D. This makes it possible to maintain the metal washer 22 relative to the belt of the collar by retaining it in both axial directions.

[0034] The support lugs also include lugs 32, which also have hooks 32A at their free ends opposite their area of ​​attachment to the outer periphery 22' of the washer 22. The lugs 32 also include axial segments 32B extending substantially axially between their attachment to the washer 22 and the hooks 32A. The lugs 32 also have hooking tabs 32C similar to the previously described tabs 30C. Finally, the lugs 32 also include wings 32D oriented in the opposite direction to the previously described wings 30D. In fact, the wings 32D are folded radially inward from the longitudinal edges of the axial segments 32B. The wings 32D have longitudinal edges 32D' that contribute to the pre-attached retention of the collar on the end of the tube by holding the washer relative to the tube 1 against radial movement.

[0035] The metal washer also has lugs 34 which have hooks 34A at their free ends opposite the outer periphery 22' of the washer 22 and have axial segments extending from the washer to the hooks, as can be seen in Figures 1 and 3. The lugs serve to angle wedging of the washer relative to the belt, with the hooks 34A engaging notches 13A in the edge 13 of the belt's side 12C.

[0036] Generally, support lugs 30 and 32 are alternately positioned on the circumference of washer 22. These lugs 30 and 32 are used to hook onto edge 13 of side 12C of belt 12 by preventing the seal from moving relative to the belt in a direction opposite to direction R1 shown in FIG. 4. Wing 30D is used to hold the washer relative to the belt by limiting movement of the washer in direction R1 relative to the belt. These lugs, as well as lug 32, have tabs 30C or 32C that are used to hold the end of the tube inside the washer. Lug 32 also has wing 32D that is used to center the tube relative to the washer.

[0037] As can be seen particularly in Figure 3, the support lugs 30 and 32 are integrally formed with a metal washer, which is in fact integrally formed from the strap by cutting, stamping and bending.

[0038] 1 to 4, the metal washer 22 and the non-metallic washers 24 and 26 are substantially planar. In fact, the bearing surfaces of the tubes 1 and 2 are formed on the front faces 1'A and 2'A of the flanges in a radially oriented manner.

[0039] However, as shown, for example, in EP 1 451 498, EP 2 598 785 or EP 3 232 107, the collar can be pre-mounted on a tube whose support surface is frustoconical. In this case, as can be seen in FIG. 8, the metal washer 122 can have a frustoconical surface, in particular a stamped frustoconical surface. The cross section in FIG. 8 shows the washer 122 and the seal 120 with lugs 30, 32 and 34 similar to those previously described. This belt 112 is similar to belt 12, except that its side surfaces 112C and 112B are inclined like a V-branch so as to be adapted to the flares of the tubes 101 and 102. Indeed, the support surface 101A of tube 101 has a frustoconical shape that forms the flare, and the support surface 102A of tube 102 has a front surface 102′A that also forms a frustoconical surface to be adapted to the above-mentioned flare. The support surface 102A formed on the back side in direction R2 relative to the frustoconical section 102'A is also frustoconical in the opposite direction and is substantially parallel to the side surface 112B of the belt 112. As shown, the metal washer has a stamped frustoconical surface 122A that conforms to the shape of the surfaces 101'A and 102'A of the tubes whose connection must be sealed with the seal 120. The non-metallic washer 124 is formed into a planar annulus by deforming its portion to conform to the frustoconical shape of the frustoconical surface of the metal washer 122.

[0040] Because washer 124 is made of a non-metallic material, it cannot always be stamped. For manufacturing cost reasons, it is advantageous to form it from a planar plate. However, an initially planar (manufactured flat) non-metallic washer can be deformed to some extent to fit the frusto-conical shape of surface 122A of washer 122.

[0041] The angle α formed by the frustoconical surface of the tube relative to the vertical direction to the axis A may be, for example, up to 20° for an initially planar non-metallic washer. Larger angles α, for example, as much as 45°, may be obtained, for example, by using non-metallic washers that are not initially planar but are formed, for example, by heating, particularly if the washer includes a thermoformable binder.

[0042] Unlike the metal washer 22, the non-metallic washer 24 can be purely annular by not having any lugs or the like attached. The non-metallic washer is held by the metal washer 22. It can be attached in various ways. For example, it can be attached to the metal washer by gluing. The adhesion can take into account the entire contact surface between the washers 22 and 24, or, conversely, can be performed by continuous or discontinuous adhesive strips with a smaller surface. For example, a cyanoacrylate type glue can be used. This glue can vaporize at high temperatures, especially those encountered in clamping systems used in combustion engine exhaust lines. The glue can be applied during assembly of the washer or pre-applied to the non-metallic washer, such as an adhesive, possibly covered with a peelable film.

[0043] The non-metallic washer 24 may be supported by the metal washer 22 by purely mechanical means, without the use of external materials such as glue. Thus, the metal washer may have retaining lugs that cooperate with the non-metallic washer to hold it relative to the metal washer. Thus, in FIGS. 1 and 5, washer 22 can be seen to have lugs 36 formed by notches in the washer and slightly straightened on its axis to form tabs with their free ends oriented toward axis A. These retaining lugs 36 thus serve to wedge and hold the non-metallic washer 24 by cooperating with its outer radial edge 24A. Similarly, as can be seen in FIGS. 2 and 6, metal washer 22 has retaining lugs 38, which are similar to retaining lugs 36 but are axially oriented on their other side to hold the non-metallic washer 26 located on the other side of washer 22.

[0044] In this example, the retaining lugs 36 or 38 retain the washers 24 or 26 by their outer radial edges. It would, of course, be possible to use similar lugs but used to retain these washers by their inner radial edges, or a combination of lugs that cooperate with the inner and outer radial edges of the washers 24 and 26.

[0045] Metal washer 22 may have an annular ridge or, more commonly, annular undulations that give it the ability to deform axially. For example, in FIG. 3, washer 22 can be seen to have a protruding annular bead 22A on one of its faces, against which non-metallic washer 24 is positioned. Non-metallic washer 24 or 26 may be completely planar over a portion thereof. It may also have annular ridge 24A, particularly whose convexity may be inverted relative to that of annular ridge 22A of washer 22, and whose diameter corresponds to that of ridge 22A. In this case, when washer 24 is assembled to washer 22, the corresponding ridges may therefore contact with their convex surfaces, which allows axial deformation of the washer under clamping force in the region of the ridge and ensures good sealing. Washer 26 may have an annular ridge 26A that may have a convexity in the same direction as annular ridge 22A so that it is partially "embedded" in this ridge, but in this case, it is rather an area of ​​the washer other than the ridge that may be deformed under the clamping force. These ridges may also be in the opposite direction. Thus, if washers 22 and 24 as just described are considered, it can be seen that they each have an annular ridge on their respective first faces disposed facing each other, thereby causing these annular ridges to contact. A reverse situation may also be provided, in which annular ridge 22A of washer 22 is oppositely oriented, i.e., by non-metallic washer 24 having an annular ridge that protrudes in a direction that forms a cavity on the side of non-metallic washer 24 and on the opposite side of washer 22, thereby rotating its recess toward washer 22. Thus, if two annular ridges are disposed on opposite faces of a washer, and when they are brought together, corresponding annular ridges together define a concave annular space. This is another way to promote sealing by promoting axial deformability of the washer.

[0046] FIG. 9 shows an example in which non-metallic washer 124 is actually formed from two basic washers, 123 and 123', respectively, secured together, for example by adhesive bonding. Each of these basic washers 123 and 123' has an annular ridge, 123A and 123B, respectively. Thus, washer 124 has an annular ridge not only on its first face, which is turned toward metal washer 22, but also on its opposite second face. Annular ridges 123A and 123B are arranged on the same diameter to define an annular space 124' between them. It can also be seen in FIG. 9 that metal washer 22 also has a protruding annular ridge 22A on its first face, with washer 124 positioned opposite the first face, thereby positioning annular ridges 22A and 123A opposite each other.

[0047] Instead of a purely convex annular ridge, metal washer 22 may have a corrugation or deformation that creates a slight bend, whereby the inner and outer radial edges of the metal washer are slightly spaced apart in the axial direction. This can be seen, for example, in FIG. 7, where metal washer 22 has such a slight bend 22B. Non-metallic washers 24 and 26, located on either side of metal washer 22, may be initially planar and deformed during tightening of the collar to conform to this bend, or may initially have such a bend.

[0048] The undulations, bends, or ridges in the non-metallic washer (or basic washer) can be created by any suitable means, such as by thermoforming, especially if the material from which the washer is made includes a thermoformable binder.

[0049] The thickness of the metal washer 22 measured on the axis between the latter two faces in the region where there are no ridges is, for example, approximately 0.2 mm to 0.8 mm, in particular approximately 0.2 mm to 0.4 mm. The thickness of the non-metallic washer measured in a similar manner may be 50% to 200%, in particular 120% to 200%, of the thickness of the metal washer.

Claims

1. 1. A clamping system for connecting a first tube (1) and a second tube (2) across an end of the first tube (1) and an end of the second tube (2), wherein the opposing ends of the tubes have support surfaces (1'A, 2'A) that protrude relative to the cylindrical outer surfaces of the tubes, the system including a tightenable collar (10) and a seal (20) disposed within the collar, the collar including a belt (12) that can cooperate with the support surfaces by its inner periphery defining a recess (15) into which the support surfaces can be inserted, the seal being supported by the collar and including an annular sealing portion (21), the annular sealing portion (21) including a metal washer (22, 122) and a non-metallic washer (24, 124) fixed to the metal washer, the non-metallic washer (22, 122) being made of a mica-based material.

2. 2. The clamping system of claim 1, wherein the metal washer (22, 122) has support lugs (30, 32) by which the metal washer and the non-metallic washer (24, 124) are supported relative to the collar.

3. 3. The clamping system of claim 2, wherein at least some of the support lugs (30, 32) are integrally formed with the metal washer.

4. 2. The clamping system of claim 1, wherein the metal washer (122) has a stamped frusto-conical surface, and the non-metallic washer (24) is formed into a planar annulus and deformed to conform to the frusto-conical shape of the frusto-conical surface.

5. The clamping system of claim 1, wherein the non-metallic washer (24, 124) is adhesively attached to the metallic washer (22, 122).

6. 2. The clamping system of claim 1, wherein the metallic washer (22, 122) has a retaining lug (36) that cooperates with the non-metallic washer (24, 124) to hold the non-metallic washer relative to the metallic washer.

7. 7. The clamping system of claim 6, wherein the retaining lug (36) is cut into the metal washer.

8. The clamping system of claim 1 , wherein the non-metallic washer (22, 122) includes a reinforcement material.

9. The clamping system of claim 1 , wherein the non-metallic washer (22, 122) includes a metal reinforcement.

10. 2. The clamping system of claim 1, wherein the metal washer (22) has an annular ridge (22A) on a first surface of the metal washer, and the non-metallic washer (22) is positioned opposite the first surface.

11. 11. The clamping system of claim 10, wherein the non-metallic washer (24, 124) has an annular ridge (24A, 123A) on a first surface of the non-metallic washer, and the first surface of the metallic washer and the first surface of the non-metallic washer are positioned opposite each other, whereby the annular ridges are in contact.

12. 12. The clamping system of claim 11, wherein the non-metallic washer (124) also has an annular ridge (123B) on its second surface, and the annular ridges of the non-metallic washer together delimit an annular space (124').

13. 2. The clamping system of claim 1, wherein the annular sealing portion (21) further includes an additional non-metallic washer (26) fixed to the metal washer (22), whereby the metal washer is located between the non-metallic washer and the additional non-metallic washer.

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