A clamping system for connecting pipes, including collars and seals.

Abstract

A clamping system is used to connect a first pipe and a second pipe, the opposite ends of which have support surfaces projecting from their cylindrical outer surfaces. The clamping system includes a clampable collar (10) and a seal (20). The collar includes a band (12) capable of interacting with the support surface of the pipe via its inner circumference, which defines an insertable reinforcement on the support surface. The seal (20), in the unclamped state, is supported by the collar and includes an annular sealing portion (21) comprising a first washer (22) and a second washer (24), the second washer being secured to the first washer by a retaining lug.

Description

Technical Field

[0001] The present invention relates to a clamping system for connecting a first tube and a second tube, the opposite ends of the first tube and the second tube having a support surface protruding relative to the cylindrical outer surface of the two tubes, the system comprising a collar and a seal, the collar being clampable around the support surface of the tube. Background Technology

[0002] Patents EP 1 451 498, EP 2 598 785, and EP 3 232 107 disclose clamping systems including collars having a band that can be clamped by reducing its diameter and a seal pre-installed in the collar. More specifically, the system includes a washer comprising a closed annular portion forming a seal and a lug connecting the seal to the collar. The closed annular seal is initially held relative to the band of the collar such that a space is provided between the seal and the inner periphery of the band, allowing the end of the tube to engage between the seal and the band. The inner tube itself is then engaged to contact the seal. This device is particularly suitable for clamping two tubes assembled together and having radially protruding surfaces that serve as supports for the clamping collar, which includes grooves that accommodate these radially protruding surfaces, and the closed annular seal itself having a shape adapted to these protrusions.

[0003] In particular, this seal can be made of stainless steel or similar metals as well as a collar band. Summary of the Invention

[0004] For some applications, particularly in the automotive sector, especially for exhaust lines of internal combustion engines, there is a need to improve the types of seals described above to withstand increasingly higher temperatures. In fact, with technological advancements, it's possible that pipe temperatures, especially at the points of contact with the seals, could reach several hundred degrees Celsius, such as 900°C or even higher. However, under such temperatures combined with high clamping stress, the metallic material of the seal will lose some of the elasticity necessary to maintain a seal. Thicker metal seals can ensure a seal under high temperatures and high clamping stress, but these seals are expensive, bulky, and less efficient in cold conditions. Therefore, if a clamping system is used to connect two pipes forming part of the exhaust line of a vehicle's hot engine, such a thick seal will be almost ineffective during engine start-up.

[0005] The present invention aims to at least substantially overcome the above-mentioned disadvantages.

[0006] Therefore, the present invention relates to a clamping system for connecting a first tube and a second tube, the opposite ends of the first tube and the second tube having a support surface protruding relative to the cylindrical outer surface of the tube, the system comprising a clamping collar and a seal, the collar comprising a band capable of defining an insertable groove on the support surface by means of its inner circumference, the seal being supported by the collar in the unclamped state and comprising an annular sealing portion comprising a first washer and a second washer fixed to the first washer, the first washer having a fixing lug that engages with the second washer to fix the second washer relative to the first washer.

[0007] Optionally, the first washer is metal.

[0008] Optionally, the fixing lug is cut out in the first washer.

[0009] Optionally, the first washer has a support lug, through which the first washer and the second washer are supported relative to the collar.

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

[0011] Optionally, at least some of the fixing lugs are formed in the supporting lugs.

[0012] Optionally, at least some of the fixing lugs are formed by radially inwardly protruding portions of the supporting lugs, particularly by folding wings toward the longitudinal edge of the supporting lugs or by cutting tabs in the supporting lugs and bending them inwards.

[0013] Optionally, the first washer has a stamped truncated conical surface, and the second washer is formed as a planar ring that can be deformed to match the truncated cone shape of the truncated conical surface.

[0014] Optionally, the second washer is made of a composite material.

[0015] Optionally, the second gasket is formed of a mica-based material.

[0016] Optionally, the second gasket contains mineral particles (especially mica or graphite) and an adhesive.

[0017] Optionally, the second washer includes a reinforcement, particularly a metal reinforcement.

[0018] Optionally, the first washer has an annular protrusion on a first surface, while the second washer is disposed against the first surface.

[0019] Optionally, the second washer has an annular protrusion on its first surface, and the first surfaces of the first washer and the second washer are disposed abutting against each other so that the annular protrusion can contact each other.

[0020] Optionally, the second washer also has an annular protrusion on its second surface, and the annular protrusion of the second washer may optionally collectively define an annular space.

[0021] Optionally, the annular sealing portion further includes an additional second washer fixed to the first washer, such that the first washer is located between the second washer and the additional second washer.

[0022] According to the invention, the seal of the clamping system therefore comprises two gaskets, which are secured together by a retaining lug on the first gasket. Thus, the two gaskets are mechanically secured together, preventing deterioration over time and facilitating implementation. The retaining lug eliminates the need for any material other than the first gasket and can be directly fabricated from it. In particular, adhesive is not required to secure the two gaskets together. The retaining lug serves to secure the two gaskets together while allowing for minor movement between them, thereby facilitating adjustment during clamping to optimize the seal.

[0023] In particular, it is possible to avoid the presence of material thickness between the two gaskets, which could be related to fixation by welding or bonding and would compromise the seal.

[0024] The combination of these two gaskets can be supported relative to the collar by utilizing a proper configuration of the seal. The portions required for sealing, namely the first and second gaskets, can be easily molded to meet the sealing needs while taking into account clamping stresses and associated temperature levels. In particular, the second gasket can be metallic or comprise materials suitable for maintaining elastic deformability at high temperatures and contributing to sealing over a wide temperature and stress range, especially mica-based materials. The seal can be lightweight, with the first gasket portion providing strength and mechanical resistance, while the non-metallic base portion contributes to its effectiveness, particularly in high temperature and high pressure ranges. Attached Figure Description

[0025] Figure 1 This is a perspective view of the clamping system according to the invention, taken from the first side.

[0026] Figure 2 yes Figure 1 The system shown is a perspective view from the other side.

[0027] Figure 3 It is an exploded perspective view showing the different components that make up the clamping system, as well as the ends of the two tubes to be assembled using the system.

[0028] Figure 4 Is Figure 1 The axial cross-sectional view in plane IV shows, on one hand, the clamping system according to the invention, and on the other hand, the ends of two tubes to be assembled using the clamping system.

[0029] Figure 5 yes Figure 1 A magnified view of detail V shown.

[0030] Figure 6 yes Figure 2 A magnified view of detail VI shown.

[0031] Figure 7 yes Figure 4 The illustration shows detail VII.

[0032] Figure 8 The alternative embodiments are with Figure 4 A similar partial axial section view.

[0033] Figure 9 This is a partial perspective view showing a variant of the seal.

[0034] Figure 10 This shows a partial axial cross-sectional view of a variant.

[0035] Figure 11 This is a partial perspective view showing a variant.

[0036] Figure 12 This is a partial view seen along the axis of the belt, showing... Figure 11 A variant of . Detailed Implementation

[0037] Figure 1 A clamping collar 10 including a band 12 is shown, the ends of which are radially raised to form clamping lugs 12A and 12B, respectively. To clamp the collar, the diameter of the band is reduced by the engagement of a clamping screw 14 with the clamping lugs 12A and 12B. The shank 14B of the screw passes through a hole in the clamping lug, its head 14A engages with lug 12A, and a nut 14C is provided at the opposite end, which in this case engages with lug 12B via a spacer 14D.

[0038] The belt 12 has an inner groove 15 disposed between the two side wings 12C and 12D of the belt (in Figure 4 (More obvious in the middle). The seal 20 is located inside the belt. For example... Figure 4As shown, this clamping system is used to connect two tubes 1 and 2, whose ends are provided with support surfaces 1A and 2A. To connect these tubes, their ends are joined together until they are axially positioned in the groove 15, and the diameter of the band is reduced so that the side flanges 12C and 12D press against the support surfaces 1A and 2A. In this case, the support surfaces 1A and 2A are formed on the radial flanges at the ends of tubes 1 and 2. As shown, a seal 20 is disposed inside the collar. To connect tubes 1 and 2, the front surfaces 1'A and 2'A of the ends of tubes 1A and 2A are positioned on either side of the annular sealing portion 21 of the seal 20.

[0039] Within the meaning of this invention, the forward direction of tube 1 or 2 is the direction toward another tube 2 or 1 when their ends are brought together to assemble the tube. Therefore, support surfaces 1A and 2A are formed on the radial flanges at the ends of the tubes. The backward direction is obviously the opposite direction. For the element, the inward direction is the direction toward the axis A of the belt. The outward direction is the opposite.

[0040] The annular sealing portion includes a first washer 22 and a second washer 24 fixed to the first washer. In this case, as considered comprehensively... Figure 1 , Figure 2 and Figure 3 As understood, the annular sealing portion includes a first washer 22, a second washer 24 disposed on a first surface of the first washer, and an additional second washer 26 disposed on the other surface of the first washer. Therefore, the first washer 22 is sandwiched between the second washers 24 and 26.

[0041] For example, the first washer 22 can be made of the same metal as belt 12, such as stainless steel. The second washers 24 and 26 can be formed of metallic or non-metallic materials, particularly composite materials. They can be formed of mica-based materials. They can be formed of the same or different materials, for example, one formed of a metallic material and the other of a composite material, such as a mica-based material. When they are non-metallic washers, the second washers can contain mineral particles (particularly mica or graphite) and a binder. The thicknesses of the two washers can be the same or different, regardless of whether they are formed of the same material. The second washers may include reinforcements, particularly metallic reinforcements, to support the non-metallic material, particularly mica or graphite-based composite materials. For example, the reinforcement can be a fine metal mesh.

[0042] Washers 24 or 26 are “non-metallic” meaning that the washer does not contain metal, or if it does contain metal, such as metal reinforcement, the metal mass constitutes only a small fraction of the mass of the washer, for example, no more than 40% of the mass of the washer, and especially no more than 20% or 30%.

[0043] The second washers 24 and 26 are supported by the first washer 22. Therefore, as Figures 1 to 3 As shown, the first washer 22 has a support lug, through which the first and second washers are supported relative to the collar 10. Therefore, the seal is pre-installed in the belt, meaning that the seal is supported by the collar before the collar is placed on the tube and clamped, allowing the collar and seal to be treated as a single unit.

[0044] Furthermore, the first washer may also have a support lug for pre-installing a washer-equipped collar onto one of the tubes to be assembled. Thus, the assembly formed by the collar and seal can be positioned at one end of a tube and held there before the end of another tube is placed and the collar is clamped. The same lug can have a dual function: both for pre-installing the seal in the belt and for pre-installing the assembly formed by the collar and seal at the end of one of the tubes. These support lugs are supported by the outer periphery of the first washer 22 (away from the belt axis A).

[0045] In this case, three different types of lugs are shown. From Figure 7 and Figure 9 As can be better seen in the image, the support lugs 30 have hook-shaped curved ends 30A so that they can hook onto the edge 13 of the side wing 12C of the band 12. Between the connection area between these support lugs 30 and the outer periphery 22' of the first washer 22 and the hook 30A, these support lugs 30 have an axial segment 30B that extends substantially axially, that is, substantially parallel to axis A. As shown in... Figure 7 As can be seen more clearly, on the one hand, the axial segment 30B has a hook-and-loop tab 30C, which is cut out in the axial segment 30B and folded radially inward by extending in the direction from the hook 30A to the outer periphery 22' of the first washer 22 toward its free end. The tab 30C is used to clamp the washer on the support surface 1A of the tube 1 to retain the collar pre-installed at the end of the tube. It can be seen that, according to Figure 4 As shown by arrow R1, the orientation of these tabs 30C prevents the tube from detaching from the gasket in the rearward direction of tube 1.

[0046] Furthermore, the support lug 30 has a wing 30D that folds radially outward from the longitudinal edge of the axial segment 30B, i.e., to move away from axis A. Additionally, when the seal is pre-installed in the gasket, the wing 30D has retaining edges 30D' facing the inner surface of the hook 30A and thus the inner surface of the side wings 12C of the band 12. These retaining edges 30D' are spaced apart from the inner surface of the hook 30A. The edges 13 of the side wings 12C are accommodated in the space between the hook 30A and the retaining edges 30D. This allows the first gasket 22 to be secured relative to the band of the collar by holding it in both axial directions.

[0047] The support lugs also include support lugs 32, which have hooks 32A at their free ends (opposite to the areas where they are attached to the outer periphery 22' of the washer 22). These support lugs 32 also include axial sections 32B that extend substantially axially between the lugs and the attachments of the washer 22 and the hooks 32A. These support lugs 32 also have hook-and-loop tabs 32C similar to the aforementioned tabs 30C. Finally, these support lugs 32 also include wings 32D, but the orientation of the wings 32D is opposite to that of the aforementioned wings 30D. In fact, the wings 32D are radially folded inward from the longitudinal edge of the axial section 32B. These wings 32D have longitudinal edges 32D' that help to pre-install the collar on the end of the tube 1 by maintaining radial displacement of the washer relative to the tube.

[0048] The first washer also has a supporting lug 34, such as Figure 1 and 3 As shown, the lug 34 has a hook 34A at its free end (opposite to the outer periphery 22' of the washer 22), and also has an axial section extending from the washer toward these hooks. These supporting lugs 34 are used for the angled wedging of the washer relative to the belt, and the hooks 34A engage in notches 13A in the edge 13 of the side wing 12C of the belt.

[0049] Typically, support lugs 30 and 32 are alternately arranged on the outer periphery of the washer 22. These lugs 30 and 32 are used to prevent the seal from contacting the tape edge with the seal. Figure 4 The lugs move in the opposite direction to R1 and hook onto the edge 13 of the side wing 12C of the belt 12. The wing 30D is used to hold the washer relative to the belt by limiting the movement of the washer relative to the belt in the direction R1. These lugs, as well as lug 32, also have tabs 30C or 32C for holding the end of the tube within the washer. Lug 32 also has a wing 32D for centering the tube relative to the washer.

[0050] Especially as Figure 3 As shown, the support lugs 30 and 32 are integrally formed with the first washer. In fact, the first washer is formed integrally from a strip through cutting, stamping, and bending.

[0051] exist Figures 1 to 4 In the example shown, the first washer 22 and the second washers 24 and 26 are substantially planar. In fact, the support surfaces of tubes 1 and 2 are formed on the front surfaces 1'A and 2'A of the flange, and are radially oriented on the support surfaces of tubes 1 and 2.

[0052] However, as indicated, for example, in patents EP 1 451 498, EP 2 598 785, or EP 3 232 107, the collar can be pre-installed on a tube whose supporting surface is a truncated cone. In this case, as... Figure 8 As shown, the first washer 122 may have a truncated conical surface, particularly a stamped truncated conical surface. Figure 8 The cross-section shows a seal 120 with a gasket 122 and support lugs 30, 32, and 34 similar to the aforementioned lugs. The band 112 is similar to band 12, but its flanks 112C and 112B can be inclined like V-branches to accommodate the flares of tubes 101 and 102. In fact, the support surface 101A of tube 101 has a truncated conical shape forming the flare, while the support surface 102A of tube 102 has a front surface 102'A, which also forms a truncated conical surface to accommodate the aforementioned flare. The support surface 102A formed in the rear direction R2 relative to the truncated conical portion 102'A is also truncated conical in the opposite direction, substantially parallel to the flanks 112B of band 112. As shown in the figure, the first washer has a stamped truncated conical surface 122A, which is adapted to the shape of the surfaces 101'A and 102'A of the pipe to which it is connected, which must be sealed by the seal 120. A portion of the second washer 124 is formed as a planar ring, which can be deformed to match the truncated conical shape of the truncated conical surface of the first washer 122.

[0053] When washer 124 is made of a non-metallic base material, it cannot always be stamped. It is advantageous to form it from a flat plate for manufacturing cost reasons. However, to some extent, a non-metallic base washer that is originally flat (flat-manufactured) can be deformed to match the truncated conical shape of the surface 122A of washer 122.

[0054] For example, for a non-metallic base gasket that is initially planar, the angle α formed by the aforementioned truncated conical surface of the tube relative to the direction perpendicular to axis A is at most 20°. For example, by using a second gasket that is not initially planar but can be shaped by heating, for example (especially when it is a gasket containing a thermoformable adhesive), a larger angle of 45° can be obtained.

[0055] Unlike the first washer 22, the second washer 24 can be purely annular, without a fixing lug or the like. The second washer is supported by the first washer 22. The second washer 24 is secured to the first washer 22 by a fixing lug provided with the first washer 22. The second washer 24 can be supported by the first washer 22 using purely mechanical components without the use of external materials such as adhesive. Therefore, in Figure 1 and Figure 5 As can be seen, the first washer 22 has retaining lugs 36, which are formed by a cut in the washer that extends axially to form a tab with its free end oriented toward axis A. Therefore, these retaining lugs 36 are used to wed in and secure the second washer 24 by engaging with the outer radial edge 24A of the second washer 24. Similarly, as... Figure 2 and Figure 6 As shown, the first washer 22 has a fixing lug 38, which is similar to the fixing lug 36 but is axially oriented on the other side to fix an additional second washer 26 located on another surface of the washer 22.

[0056] In this example, the retaining lug 36 or 38 secures the washer 24 or 26 via the outer radial edge of the washer 24 or 26. Of course, similar lugs could also be provided, but securing these washers via the inner radial edge of the washer, or combinations of lugs that mate with both the inner and outer radial edges of washers 24 and 26.

[0057] like Figures 10 to 12 As shown, the support lug of the first washer may include a fixing lug to fix the second washer relative to the first washer.

[0058] therefore, Figure 10 A first washer 22 with a support lug 32 and a support lug 34 is shown. Figure 10 A second washer 24 is also shown, its outer diameter being almost equal to, but slightly smaller than, the outer diameter of the first washer 22. Therefore, the outer edge 24A of the second washer 24 substantially extends to the circle defining the outer edge of the first washer 22, between the support lugs. Figure 10 As can be seen, the supporting lug 34, or more specifically, its axial segment 34B, has a hook 34C forming a retaining lug for the second washer 24. This retaining lug 34C is cut out in the axial segment 34B, with one end near the hook 34A attached to the axial segment 34B, while the other end is free. The retaining lug 34C can be cut out in the circumferential center region of the axial segment 34B, or conversely, at the longitudinal edge of the latter. The retaining lug 34C is radially curved inward. The free end of the retaining lug 34C is radially more inward than the outer edge 24A of the second washer 24, which allows it to function as a retaining lug. When assembling the two washers, the edge 24A of the second washer 24 and / or the retaining lug 34C can be elastically deflected so that the outer edge of the second washer 24 inserts under the free end of the hook 34C.

[0059] The wing 32D supporting the lug 32 can also serve as the fixing lug of the second washer 24.

[0060] This point is Figure 11 and Figure 12 The figure most clearly shows the outer edge 24A of the second washer 24 radially extending below the wing 32D, in the space between the edge of these wing away from the hook 32A and the outer edge of the annular portion of the first washer 22. When assembling the two washers, the outer edge 24A of the second washer can be elastically deflected to insert this outer edge into this space.

[0061] The first washer 22 may have an annular protrusion, or typically an annular protrusion, thereby giving it the ability to deform axially. For example, in Figure 3 As can be seen, washer 22 has an annular flange 22A protruding from one of its faces, against which second washer 24 is disposed. The second washer 24, or additional second washer 26, can be completely planar in itself. It can also have an annular protrusion 24A, specifically, its convexity can be opposite to that of the annular protrusion 22A of washer 22, and its diameter corresponds to the diameter of protrusion 22A. In this case, when washer 24 is assembled onto washer 22, their respective protrusions can thus contact each other through their protruding surfaces, a way that allows the washer to deform axially under clamping force in the protruding area to ensure a good seal. Washer 26 can have an annular protrusion 26A in itself, the protrusion direction of which can be similar to that of annular protrusion 22A, so as to partially "embed" in the protrusion, in this case, more accurately, it is an area of ​​the washer rather than a protrusion that deforms under clamping force. These protrusions can also be in opposite directions. Therefore, considering the gaskets 22 and 24 just described, it can be seen that the annular protrusions on their respective first surfaces are arranged abutting each other so that these annular protrusions can contact each other. The opposite case can also be provided, where the annular protrusions 22A of gasket 22 are oriented oppositely, i.e., forming a hollow shape on the side of the second gasket 24, and the second gasket 24 has an annular protrusion projecting onto the opposite side of gasket 22 with its concave surface facing gasket 22. Thus, these two annular protrusions are arranged on the opposite surfaces of the gaskets, and when they are joined, the corresponding annular protrusions together define a recessed annular space. This is another way to promote axial deformation of the gasket to facilitate a seal.

[0062] Figure 9 An example is shown in which the second washer 124 is actually formed by two simple washers 123 and 123' fixed together, for example by a coupling or by a mechanically fastening lug similar to the aforementioned fastening lugs 36 or 38. Each of these simple washers 123 and 123' has annular protrusions 123A and 123B, respectively. Thus, washer 124 has annular protrusions not only on its first face facing the first washer 22, but also on its opposing second face. The annular protrusions 123A and 123B are arranged on the same diameter to create an annular space 124' between them. Figure 9 It can also be seen that the first washer 22 has an annular protrusion 22A protruding on its first surface, and the washer 124 is disposed against the annular protrusion, such that the annular protrusions 22A and 123A are disposed against each other.

[0063] Unlike a purely convex annular protrusion, the first washer 22 may have a slightly curved wave or deformation, such that the inner radial edge and the outer radial edge of the first washer are slightly spaced axially. This can be, for example, in... Figure 7 As seen in the image, the first washer 22 has this slight bend 22B. The second washers 24 and 26, located on either side of the first washer 22, may initially be flat and may deform during collar clamping to accommodate the bend, or may have this bend from the outset.

[0064] The protrusions, bends, or protrusions of the second washer (or simple washer) can be made by any suitable means, such as by thermoforming, especially when the material used to make the washer includes a thermoformable adhesive.

[0065] In areas where no protrusions are present, the thickness of the first washer 22, measured axially between its two faces, is on the order of, for example, 0.2 mm to 0.8 mm, particularly 0.2 mm to 0.4 mm. The thickness of the second washer, measured in the same manner, can be 50% to 200% of the thickness of the first washer, particularly 120% to 200%.

Claims

1. A clamping system for connecting a first pipe and a second pipe (1, 2), the opposite ends of the first pipe and the second pipe having support surfaces (1'A, 2'A) projecting relative to the cylindrical outer surface of the pipe, the system comprising a clamping collar (10) and a seal (20), the collar comprising a band (12) capable of defining, through its inner circumference, a groove (15) into which the support surface can be inserted, the seal being supported by the collar in an unclamped state, and comprising an annular sealing portion (21), the annular sealing portion comprising a first washer (22, 122) and a second washer (24, 124) fixed to the first washer, the first washer (22, 122) having a fixing lug (36, 38, 34C, 32D) engaging with the second washer (24, 124) to fix the second washer relative to the first washer.

2. The clamping system according to claim 1, wherein, The first washer (22) is metal.

3. The clamping system according to claim 1, wherein, The fixed lugs (36, 38, 34C, 32D) are cut out in the first washer (22).

4. The clamping system according to claim 1, wherein, The first washer (22, 122) has a support lug (30, 32, 34), and the first washer and the second washer (24, 124) are supported relative to the collar by the support lug.

5. The clamping system according to claim 4, wherein, At least some of the supporting lugs (30, 32, 34) are integrally formed with the first washer (22).

6. The clamping system according to claim 4, wherein, At least some of the fixed lugs (36, 38, 34C, 32D) are formed in the supporting lugs (30, 32, 34).

7. The clamping system according to claim 6, wherein, At least some of the fixed lugs (36, 38, 34C, 32D) are formed by radially inwardly protruding portions supporting lugs (32, 34).

8. The clamping system according to claim 6, wherein, At least some of the fixed lugs (34C, 32D) are formed by folding at least one wing (32D) toward the longitudinal edge of the support lug (32) or by cutting out a tab (34C) in the support lug (34) and bending it inward.

9. The clamping system according to claim 1, wherein, The first washer (122) has a stamped truncated conical surface, and the second washer (24) is formed as a planar ring and deformed to match the truncated conical shape of the truncated conical surface.

10. The clamping system according to claim 1, wherein, The second gasket (22, 122) is made of composite material.

11. The clamping system according to claim 1, wherein, The second gasket (22, 122) is formed of mica-based material.

12. The clamping system according to claim 1, wherein, The second gasket (22, 122) contains mineral particles and an adhesive.

13. The clamping system according to claim 12, wherein, The mineral particles include one or more of mica and graphite.

14. The clamping system according to claim 1, wherein, The second washer (22, 122) includes a reinforcement.

15. The clamping system according to claim 1, wherein, The second washer (22, 122) includes a metal reinforcement.

16. The clamping system according to claim 1, wherein, The first washer (22) has an annular protrusion (22A) on a first surface of the first washer, and the second washer (22) is disposed against the first surface.

17. The clamping system according to claim 16, wherein, The second washer (24, 124) has an annular protrusion (24A, 123A) on its first surface, and the first surface of the first washer and the first surface of the second washer are disposed abutting against each other such that the annular protrusion contacts each other.

18. The clamping system according to claim 14, wherein, The second washer (124) also has an annular protrusion (123B) on its second surface, and the annular protrusion of the second washer optionally defines an annular space (124').

19. The clamping system according to claim 1, wherein, The annular sealing portion (21) further includes an additional second washer (26) fixed to the first washer (22), with the first washer located between the second washer and the additional second washer.

Images