Sealing ring for sealing flange connections

Abstract

Sealing ring for sealing flange connections with a sealing section (1) and a ring section (2) adjoining the sealing section (1) in a radial direction (R), wherein at least one area adjoining the ring section (2) on the side facing away from the sealing section is provided for a clamping arrangement on an associated contact surface (21), wherein the ring section (2) transitions via a connecting web (5) into a circumferential collar (4) having a free end (6) and several radial retaining projections (3) are formed by radial protrusions of the collar (4) at its free end (6).

Description

[0001] The invention relates to a sealing ring for sealing flange connections, comprising a sealing section and an annular section adjoining the sealing section in a radial direction. At least one area adjoining the annular section on the side facing away from the sealing section is designed for a clamping arrangement on an associated contact surface, particularly one extending radially. The contact surface is formed, in particular, on a flange. The arrangement of the individual sections relative to one another in a radial direction is not limited to specific designs; the edge for the clamping arrangement in a radial direction can be located either on an inner or an outer side of the sealing ring.

[0002] When assembling flange connections, it is generally necessary to place a sealing ring between the two corresponding sealing surfaces of the flanges to prevent the escape of gases and liquids. These sealing rings can be arranged either in a primary force-fit or a secondary force-fit configuration. In a primary force-fit configuration, the forces occurring during clamping are transmitted entirely through the sealing ring, while in a secondary force-fit configuration, the majority of the force is transmitted directly through the flanges, with only a small portion passing through the sealing ring itself.

[0003] Regardless of the specific arrangement, it is essential that the sealing ring is correctly positioned during assembly. This is the only way to ensure that the sealing ring is evenly compressed when the clamping elements are tightened, thus achieving the required sealing effect. It is crucial to prevent the sealing ring from slipping or even falling off during assembly. However, achieving a correctly oriented, and especially centered, position is particularly difficult during assembly. For example, if the two flanges and the gap between them are vertically aligned, gravity can cause the sealing ring to slip or fall off before the two flanges are clamped together. Furthermore, the sealing ring can also slip during clamping, making it essential to center and hold the sealing ring securely before assembly.

[0004] In practice, such precise positioning is usually achieved by using aids, particularly adhesives, which are applied to the sealing ring and / or the flange and fix the sealing ring in its desired position on the flange. However, a problem arises because the adhesive is always located between the sealing ring and the sealing surface of the flange that interacts with the sealing ring, thus impairing the sealing effect. For this reason, the extensive use of adhesives should be avoided, and fixing with adhesive should only be achieved via a few small spots if absolutely necessary in justified exceptional cases.A corresponding instruction can be found in TRBS 2141-3 – Hazards from vapor and pressure during the release of media – according to which adhesive fixatives should only be used if other means are unavailable. However, in practice, it is often the case that this instruction is disregarded and that instead of individual adhesive spots, a large area of ​​adhesive is applied.

[0005] It is also known from practice to achieve fixation using retaining projections, for which various concepts have been developed. For example, US 2,466,263 describes a so-called spiral wound gasket with individual retaining projections arranged on the outer circumference. These retaining projections can be formed in different ways, for example, by making adjacent incisions in an outer ring and bending out the area between the two incisions. These areas then form the retaining projections, which enable the sealing ring to be clamped to a step of a flange.

[0006] Such a design therefore requires that the flanges or the flange itself has a groove or at least a step against which the flange can be clamped via the retaining projections.

[0007] Alternatively, simple radially extending projections are also described, which allow for centering but not a clamping connection or frictional connection with the step of a flange.

[0008] According to GB 721, 040, a separate wire ring with projections is used to center a sealing ring on a flat flange wall. This wire ring is bent inwards at several circumferential positions, thereby also providing a clamping fixation.

[0009] DE 3729109 A1 relates to a flat gasket with angled hooks as retaining projections, which are attached to the sealing ring by welding.

[0010] Further embodiments are known, for example, from US 2,311,577, US 2,339,478 or EP 0 922 897 B1.

[0011] Although the sealing rings already known from the prior art are fundamentally suitable for fixing the sealing ring in a flange arrangement that is not yet clamped together, there is nevertheless a need to further develop these sealing rings in such a way that they can be manufactured particularly easily and in large quantities, while at the same time enabling effective fixing and centering.

[0012] This problem is solved by a sealing ring according to claim 1, a flange connection according to claim 9 and a method for assembling a flange connection according to claim 11.

[0013] According to the invention, the ring section transitions via a connecting web into a circumferential collar having a free end. The collar simultaneously constitutes the section of the sealing ring by which the sealing ring is clamped to a radially oriented contact surface.

[0014] In principle, the collar can be manufactured with precision, with tolerances in the hundredths of a millimeter range. This takes into account the fact that, due to its ring shape and uniform structure around its circumference, the collar can only be minimally elastically deformed, and therefore large manufacturing tolerances cannot be compensated for by a larger oversize or undersize.

[0015] According to the invention, several radial retaining projections are attached to the side of the ring section facing away from the sealing section. These retaining projections are formed by radial bulges in the collar at its free end. Since the collar at least partially, but preferably completely, encloses the ring section, its ring-shaped design results in poor spring properties, as explained above. Consequently, the collar alone only provides sufficiently clamping or locking connections with tight manufacturing tolerances. However, only a locking connection can ensure that the sealing ring not only does not shift radially but is also effectively secured against falling out or axial displacement.For this reason, retaining projections are created by radial bulges in the collar, which, compared to the collar itself, enable improved spring clamping or an effective connection. These retaining projections can be elastically deformed. Therefore, the collar is undersized and the retaining projections are oversized relative to the radius of the step. This generally applies to a design where the retaining projections are located on an outer edge of the sealing ring. In a design with the retaining projections on an inner edge, the collar is oversized and the retaining projections are undersized.

[0016] When designed with appropriately shaped retaining projections, tight manufacturing tolerances are not required. Manufacturing tolerances in the millimeter range are sufficient, as the retaining projections can be elastically deformed much more easily, allowing for a clamping arrangement of the sealing ring even with larger oversizes.

[0017] The particular advantage here is that the retaining projections can be easily manufactured by means of indentations in the collar, without the need for attaching additional retaining elements or cutting and bending them out of the sealing ring. Since the retaining projections are thus plastically formed from the collar, metal is the preferred material for the collar.

[0018] In a further development of the invention, the ring section and the collar with the retaining projections are formed on a common, preferably metallic, ring body. This is thus a one-piece embodiment, with the ring body being an integral component that provides both the ring section and the collar with the retaining projections. Alternatively, it is also conceivable that the collar and the ring body are manufactured separately and then joined together, for example by welding.

[0019] Regardless of whether the design is one-piece or multi-piece, a bulge is always provided between the collar and the ring body, so that the free end of the collar is spaced away from the edge of the ring body. The collar connects to the ring body solely via the bridge, with the bulge preferably having a V-shaped or U-shaped cross-section.

[0020] In a further development of the invention, the support for the sealing section is also formed on the common ring body. Thus, the support for the sealing section, the ring section, and the collar with its retaining projections are all integrally formed on a common ring body, which simplifies manufacturing and ensures mechanical strength at the connection points between the respective sections. However, it is also fundamentally within the scope of the invention for the support for the sealing section and the ring section to be formed on a single integral component, with the collar being manufactured separately and subsequently joined to this integral component.

[0021] Provided that at least the ring section and the sealing section are integrally connected, the sealing section is preferably designed as a serrated profile gasket, in which case the carrier has several serrated edges arranged radially in succession. Serrated profile gaskets are particularly well suited for sealing flange connections used under extreme operating conditions. Preferably, a sealing surface is provided on one or both sides of the carrier, extending at least partially along the sealing section. In such a case, the serrated edges interact directly with the sealing surfaces, resulting in several radially arranged sealing peaks at which the sealing surface is then pressed particularly firmly between the serrated edges and the sealing surface of the flange.

[0022] The use of sealing pads is not limited to designs where the sealing section is configured as a serrated profile seal. The carrier can also be flat and therefore without serrations. Furthermore, the integration of so-called corrugated rings is also possible, with the corrugated ring positioned between the flat carrier and the sealing pad. In such a case, the sealing section is designed as a corrugated ring seal. Alternatively, hybrid designs are also conceivable, such that, for example, one side of the sealing ring is a corrugated ring seal and the other side of the carrier is flat with a sealing pad. Depending on the operating conditions, the sealing pad itself can be made of polytetrafluoroethylene (PTFE), graphite, mica, aluminum, or silver.

[0023] According to an alternative embodiment, the sealing section is formed on an annular sealing body and this is connected to the annular body, wherein the sealing body is designed as a spiral seal.

[0024] Thus, the sealing section and the ring section are formed on different components and fixed together using appropriate methods, such as welding or shrink-fitting. With this design, it is possible to provide a sealing element formed from a spirally wound band. Typically, such a spiral seal consists of a spirally wound combination of a soft material band made of graphite, PTFE, or mica and a profiled stainless steel or steel band. The soft material band protrudes from the steel or stainless steel band and performs the function of the actual sealant.

[0025] For centering, such spiral seals typically have a centering ring in which the wound bands are arranged, thus preventing them from unwinding. In this case, the ring body takes on the function of the centering ring, so this design is only practical if the sealing section in the form of the spiral seal and the ring body as the centering ring are provided by different components.

[0026] The invention also relates to a flange connection with a first and a second flange and a sealing ring according to the invention arranged between the flanges, wherein the first flange has a step with a radially directed contact surface and wherein the sealing ring with its edge on the side of the ring section facing away from the sealing section clamps against the contact surface via the retaining projections.

[0027] As previously explained, the sealing ring according to the invention is suitable for its intended use when the flange connection has a contact surface formed by a step. The sealing ring itself can be arranged radially inside or outside the contact surface. In an inside arrangement, the collar has an undersized diameter relative to the contact surface, while the retaining projections have an oversized diameter. In an outside arrangement of the sealing ring, the retaining projections are undersized and the collar is oversized.

[0028] This design ensures that the retaining projections can be clamped against the contact surface and form a friction-fit connection. This prevents both centering and axial slippage or falling out. The undersize or oversize of the retaining projections relative to the contact surface must be selected so that the sealing ring is easy to insert and the resulting deformation exerts a contact force on the contact surface from the retaining projections, providing sufficient friction.

[0029] In a further development of the flange connection according to the invention, the step is formed by a recess from an end face, preferably by a groove. In the case of a groove, the step can then relate to either the radially inner or the radially outer part of the groove, so that, depending on the design of the sealing ring, the retaining projections are clamped against a radially inner or a radially outer contact surface. Crucially, the width and height of the groove must be adapted to the sealing ring used, allowing the sealing ring and its sealing section to deform sufficiently while simultaneously ensuring that the groove width allows for complete retention even in a deformed state of the sealing ring. Since the use of grooves is particularly advantageous when the sealing ring is arranged in a force-by-flow configuration, an incorrectly designed groove or...An incorrect alignment between the groove and the sealing ring can lead to the flanges not resting directly on each other, so that consequently the entire clamping force is transmitted via the sealing ring. This is therefore an incorrect arrangement with a force-fit connection.

[0030] The flange connection according to the invention is not limited to the use of specific flange types. For example, it can be a so-called weld neck flange, which is welded to the end face of a pipe stub. Alternatively, the weld neck flanges can also be so-called slip-on weld flanges, which are slipped over the pipe stub and then welded. In such a case, it is also conceivable that the pipe stub projects axially beyond the flange, so that the outer wall of the pipe stub then forms the contact surface for the retaining projections of the sealing ring. Furthermore, the flange connection can also be a so-called loose flange connection, in which case the pipe stubs have corresponding angled sections against which the loose flanges rest and by means of which the pipe stubs can then be clamped together.

[0031] The invention further relates to a method for assembling a flange connection, wherein a first flange is provided which has a step with a radially oriented contact surface. As already explained, this step can be part of a groove. In a next step, a sealing ring according to the invention is provided which, depending on the design of the first flange, has either a radially external or radially internal collar. This sealing ring is then mounted on the first flange by applying the sealing ring, whereby a clamping connection is formed between the sealing ring, via the retaining projections, and the contact surface.This is due to the fact that the sealing ring is designed such that the retaining projections are undersized when arranged radially outside the contact surface and oversized when arranged radially inside. When the ring is fitted, the collar or the retaining projections are elastically deformed, thereby generating a contact force against the contact surface.

[0032] In the next step, a second flange is provided, the design of which is adapted to the first flange. If the sealing ring on the first flange is inserted into a groove that completely accommodates the sealing ring, the second flange can have a design with a flat bearing surface.

[0033] Finally, the first and second flanges are clamped together, with the sealing ring being positively engaged. This positive engagement is achieved by the sealing ring projecting axially beyond the step. The extent of this projection depends primarily on the type of gasket and the clamping force applied to the flanges. The clamping process deforms the sealing ring, creating an effective sealing surface in contact with the sealing surfaces of the flanges.

[0034] The invention will now be explained in more detail with reference to drawings illustrating only exemplary embodiments. The drawings show: Fig. 1 a sealing ring according to the invention in a design as a serrated profile seal, Fig. 2 a sealing ring according to the invention in a design as a spiral seal, Fig. 3 a top view of the sealing ring according to Fig. 1, Fig. 4a and Fig. 4b a flange connection according to the invention.

[0035] The Fig. Figure 1 shows the sealing ring according to the invention with a sealing section 1 and a ring section 2 adjoining the sealing section 1 in the radial direction R. In principle, it is also possible for the ring section 2 to adjoin the sealing section 1 radially on the inside.

[0036] A collar 4 is provided around ring section 2, which is connected to ring section 2 via a connecting bridge 5. In the case of the Fig. In the example shown in Figure 1, the collar 4 and the ring section 2 are formed integrally from a common ring body 15, thus eliminating the need for additional joining measures. The collar 4 also has a free end 6, with retaining projections 3 formed at its free end 6 by a radial bulge of the collar 4. These retaining projections 3 abut the side of the ring section 2 facing away from the sealing section 1. The retaining projections 3 extend circumferentially U over a specific angle, preferably between 5° and 15°.

[0037] Furthermore, a recess 7 is provided to form the collar 4, which in the present example has a V-shape in cross-section.

[0038] The sealing ring is designed as a so-called serrated profile seal, wherein the carrier 8 of the sealing section 1 has several serrations arranged radially R. The carrier 8 of the sealing section 1, the ring section 2, and the collar 4 with the retaining projections 3 are also formed from a common ring body 15. It is therefore an integral component. The ring body 15 is made of metal, so that both the serrations and the recess 7 for the collar 4 can be formed by conventional machining processes, e.g., by turning.

[0039] The shaft crests are further provided on both sides of the carrier 8 of the sealing section 1, wherein a sealing pad 9a, 9b made of polytetrafluoroethylene (PTFE), graphite, mica, aluminum or silver is arranged on both sides of the carrier 8. During the assembly of the sealing ring, the sealing pads 9a, 9b are pressed against the carrier 8, so that sealing peaks are formed on the shaft crests, thereby creating an effective sealing effect.

[0040] The Fig. Figure 2 shows a sealing ring, wherein the sealing section 1 is formed on an annular sealing body 10. The sealing body 10 is connected to the annular body 15, on which the annular section 2 and the collar 4 with the retaining projections 3 are arranged. The sealing body 10 is designed as a so-called spiral seal and projects axially X on both sides opposite the annular section 2. During assembly, the soft material strips 11 made of graphite, PTFE, or mica are deformed, thus creating a sealing effect. The soft material strips 11 are arranged between steel strips 12, preferably stainless steel strips, wherein both the soft material strips 11 and the steel strips 12 have a central groove 13 by which the wound soft material strips 11 and steel strips 12 can be held in position axially X.Accordingly, the ring body 15, on which the ring section 2 is formed, has a notch 14 which is designed to accommodate the groove 13 of the sealing body 10.

[0041] The sealing ring according to the Fig. 2 is analogous to the one in the Fig. The sealing ring shown in Figure 1 is designed such that the retaining projections 3 are arranged on an outer edge in the radial direction R. Of course, this can be deviated from, so that the retaining projections 3 are then arranged on a radially inner edge.

[0042] The Fig. 3 shows the one in the Fig. Figure 1 shows a top view of the sealing ring, with the shaft crests of the carrier 8, on which the sealing section 1 is formed, concealed by the sealing surface 9a. In the radial direction R, the ring section 2 and the collar 4 then adjoin it, with a total of four retaining projections 3 formed on the collar 4 in the circumferential direction U by radial bulges at the free end 6 of the collar 4. The four retaining projections 3 ensure a clamping arrangement of the sealing ring 1, although a corresponding effect would also occur with just three retaining projections 3. The number of retaining projections 3 is not limited within the scope of the invention and can be adjusted accordingly depending on the size of the sealing ring.

[0043] The Fig. 4a and Fig. Figure 4b shows a flange connection with a first flange 16 and a second flange 17. The first flange 16 has a recess 19 extending circumferentially U along an end face 18, on which a sealing ring according to the invention is arranged. The recess 19 forms a step 20 with a radially extending contact surface 21. The retaining projections 3 are arranged according to the Fig. 4a on a radially inner edge of the sealing ring and according to the Fig. 4b are formed on a radially outer edge of the sealing ring. Thus, step 20 and contact surface 21 also refer to different sections of the first flange 16.

[0044] The first flange 16 and the second flange 17 are further connected to each other by clamping means 22, the clamping means 22 preferably being screw connections. The clamping means 22 clamp the two flanges 16, 17 together, thereby compressing the sealing ring.

Claims

[1] Sealing ring for sealing flange connections with a sealing section (1) and a ring section (2) adjoining the sealing section (1) in a radial direction (R), wherein at least one area adjoining the ring section (2) on the side facing away from the sealing section is provided for a clamping arrangement on an associated contact surface (21), wherein the ring section (2) transitions via a connecting web (5) into a circumferential collar (4) having a free end (6) and several radial retaining projections (3) are formed by radial protrusions of the collar (4) at its free end (6). [2] Sealing ring according to claim 1, characterized by , that the ring section (2) and the collar (4) with the retaining projections (3) are formed from a common ring body (15). [3] Sealing ring according to claim 1 or 2, characterized by, that a V-shaped or U-shaped recess (7) is provided between the collar (4) and the ring section (2). [4] Sealing ring according to one of claims 2 or 3, characterized by , that a support (8) of the sealing section (1) is also formed from the common ring body (15). [5] Sealing ring according to claim 4, characterized by , that the sealing section (1) is designed as a comb profile seal and the support (8) has several wave crests in succession in the radial direction (R). [6] Sealing ring according to claim 4 or 5, characterized by , that an annular sealing surface (9a, 9b) is arranged on one or both sides of the support (8), which extends at least partially along the sealing section. [7] Sealing ring according to one of claims 1 to 3, characterized by, that the sealing section (1) is formed on an annular sealing body (10) and this is connected to the annular body (15), wherein the sealing body (10) is designed as a spiral seal. [8] Flange connection with a first and a second flange (16, 17) and a sealing ring arranged between the flanges (16, 17) according to one of claims 1 to 7, wherein the first flange (16) has a step (20) with a radially extending contact surface (21), wherein the sealing ring with its edge on the side of the ring section (2) facing away from the sealing section (1) preferably clamps against the contact surface (21) via the retaining projections (4). [9] Flange connection according to claim 8, characterized by , that the step (20) is formed via a recess (19) from an end face (18), preferably via a groove (19). [10] Method for assembling a flange connection, comprising the steps: - Providing a first flange (16) having a step (20) with a radially (R) directed contact surface (21), - Provision of a sealing ring according to any one of claims 1 to 7, - Mounting the sealing ring on the first flange (16) by placing the sealing ring in a clamping connection between the sealing ring and the contact surface (21), preferably via the retaining projections (3), - Provision of a second flange (17), - Clamping the first flange (16) and the second flange (17) together with force-fit engagement of the sealing ring.

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