Connection arrangement with a press connection

Abstract

Connection arrangement comprising a pipe end section (1) of a pipe and another component having a tubular connecting stub (2), between which a press connection exists, as well as a sealing ring (3) and a retaining element (4, 5, 6) comprising a cutting ring (4, 5), which as further components of this press connection are inserted into a chamber (7) formed between an outer shell surface (13) of the pipe end section (1) inserted into the connecting stub (2) via a stub opening (15) and an inner shell surface (14) of the connecting stub (2) which is enlarged in its cross-section in this area, wherein the cutting ring (4, 5) arranged between the stub opening (15) and the sealing ring (3) with respect to the axial extension direction (a) of the connection arrangement, consists of a base body (4) having a discontinuity (11) in the circumferential direction (u) and of a retaining element (4, 5) projecting from the base body (4) along its circumference.a cutting ring (4, 5) consists of cutting elements (5) inclined against the axial extension direction (a) and is firmly connected to the retaining element (4, 5, 6) with a support ring (6) which is inserted between the base body (4) and the cutting elements (5) of the cutting ring (4, 5) and which also has a break (12) in the circumferential direction (u), characterized in that a spot weld connection (10) exists within the press fit between the cutting ring (4, 5) with its cutting elements (5) arranged on the side facing away from the sealing ring (3) and inclined towards the sealing ring (3), and the support ring (6) which together with the cutting ring (4, 5) forms the retaining element (4, 5, 6) and the inner cylindrical surface (14) of the connecting stub (2), wherein the cutting ring (4, 5)5) at the front edge of one of the ends framing the interruption (11) of its base body (4) a recess (9) extending into the base body (4) in a U-shape with legs parallel to each other is formed, into which a tongue (8) extending from the front edge of the other end of the base body (4) in the circumferential direction (u) projects.

Description

[0001] The invention relates to a connection arrangement with a press connection. Components of the connection arrangement are a pipe end section, namely the end section of a pipe intended for the construction of a piping system, and another component, such as an assembly or a fitting, of the same piping system. These components are connected to one another in the press connection by including elements that mechanically hold the connection arrangement together and seal against the escape of a fluid transported through the piping system. The invention relates in particular to the specific design of said press connection, including the arrangement and design of the elements incorporated into this press connection to support the mechanical cohesion and for sealing.

[0002] Piping systems comprising pipes and other components are constructed for a wide variety of purposes. Since the pipes usually have a standardized, but in any case limited, length, piping systems typically comprise multiple pipes, making it necessary, among other things, to connect the respective pipes at their ends using a suitable connection technology. Furthermore, such connections are also necessary between a pipe and, for example, an assembly or a valve, i.e., a component that is not a pipe.

[0003] To create such connections, a connection technique has been established in which the components of a piping system to be connected are joined using a press connection. Using a seal or sealing ring inserted into the press connection, such press connections are widely used in piping systems for conveying a fluid, i.e., a gas or liquid. The connection arrangement presented below is intended particularly for use in the latter application, but is expressly not limited to it.

[0004] In any case, when connecting fluid-carrying pipes, it is generally essential to incorporate a sealing ring into the press connection as part of the connection assembly to prevent fluid leakage in the area of ​​the press connection during intended use. Furthermore, it is common to incorporate additional retaining elements, such as a cutting ring, into the press connection to improve the mechanical hold of the press connection and thereby make it particularly resistant to pull-out forces that may potentially occur in the axial direction on the components of the piping system connected by the press connection.

[0005] US 5,108,134 A, for example, describes a corresponding connection arrangement. In this arrangement, a sealing ring and a cutting ring are inserted adjacent to one another into a connecting piece (for example, a fitting) with an appropriately structured inner surface, into which a pipe end section is to be inserted to form a press connection. The cutting ring has a plurality of cutting elements along its circumference on the side facing the sealing ring. However, there is a risk that the sealing ring will be damaged during the creation of the press connection by the cutting elements of the cutting ring, which deforms under the action of pressure and may shift in the axial direction. This could potentially lead to leaks at the press connection during operation.

[0006] Another disadvantage is that, according to this solution, the cutting ring is arranged first, starting from the axial end of a pipe end section inserted into the nozzle, and then, on the side facing away from the front pipe end, the sealing ring. The cutting ring is therefore not included in the sealing effect achieved by the sealing ring against the medium transported through the piping system. A fluid, for example, conveyed through the area of ​​the press connection could therefore potentially penetrate the cutting ring and cause it to corrode and subsequently become so damaged that it can no longer reliably fulfill its function of improving mechanical hold against axially acting pull-out forces.

[0007] The solution described in EP 1 593 899 B1 prevents damage to the sealing ring caused by the cutting ring during the press connection. To this end, an assembly consisting of the sealing ring and the cutting ring, along with a separating ring arranged between them, is inserted into the press connection. The separating ring prevents damage to the sealing ring caused by the cutting ring during the press connection. Furthermore, in this solution, the sealing ring protects the cutting ring from contact with a potentially corrosive medium flowing through the connected components, thus protecting it from corrosion.

[0008] A solution that does not require a separating ring is disclosed in DE 10 2022 115 161 A1. In this solution, the sealing ring and the cutting ring, which has a circumferential interruption, are jointly inserted into a chamber formed between the inside of a connecting piece, for example, a fitting, and the outside of a pipe end section. The tooth-shaped cutting elements are arranged on the side of the cutting ring's base body facing away from the sealing ring, so that the cutting ring cannot damage the sealing ring, which is arranged further toward the pipe end, when creating the press connection. Furthermore, the cutting ring is firmly connected to a support ring inserted between its base body and the cutting elements, which additionally stabilizes the cutting ring against deformation during pressing.However, it has been shown that even these measures do not always guarantee a mechanically stable and absolutely tight press connection with regard to axial tensile forces. This is especially true if undesirable axial displacement of the cutting ring or individual sections of its circumference occurs when inserting the pipe end section into the connecting piece.

[0009] The object of the invention is to provide a solution that avoids the aforementioned disadvantages. To this end, a connection arrangement with a press connection is to be provided that ensures a particularly high degree of reliability with regard to mechanical stability against axial tensile forces occurring at the press connection and its tightness.

[0010] The object is achieved by a connecting arrangement having the features of claim 1. Advantageous embodiments and further developments of the invention are provided by the subclaims.

[0011] The connection arrangement proposed to solve the problem is also a connection arrangement comprising a pipe end section of a pipe and another component having a tubular connecting piece, between which a press connection exists. Within the press connection, a sealing ring and a retaining element are inserted as additional components into a chamber formed between an outer surface of the pipe end section inserted into the connecting piece via a piece opening and an inner surface of the connecting piece (originally) whose cross-section is expanded in this section, and are pressed together in this area.

[0012] The cutting ring, as is already known in principle, has a base body with an interruption in the circumferential direction and preferably tooth-like cutting elements protruding from the base body along the circumference. These cutting elements are arranged on the side of the base body facing away from the sealing ring and are inclined towards the sealing ring both in the axial direction of extension of the connecting arrangement. The support ring is firmly connected to the holding element mentioned above as a component of the press connection by means of the support ring inserted between the base body and the cutting elements of the cutting ring, which likewise has an interruption in the circumferential direction. Within the press connection, a spot weld exists between the cutting ring, the support ring which together with it forms the holding element, and the inner circumferential surface of the connecting piece.

[0013] The retaining element to be used to produce the connecting arrangement according to the proposed solution is provided with a cutting ring having a circumferentially extending tongue on the front edge of one of the ends enclosing the interruption in its base body, as well as a U-shaped recess extending into the base body at the other end of the base body, starting from its front edge. This retaining element is inserted into the connecting piece after the sealing ring in the region of the chamber provided between the pipe end section and the connecting piece of the other component (fitting, unit, valve, or the like). This is done in such a way that the cutting elements on the base body of the cutting ring are arranged on the side facing away from the sealing ring and inclined towards the sealing ring, with the tongue on the base body of the cutting ring protruding into the recess formed at its other end.

[0014] After inserting the retaining element, at least one spot weld is created between the base body of its cutting ring and its support ring, as well as the inner surface of the connecting piece. The pipe end is then inserted into the connecting piece, and finally, the press connection is created by applying pressure to the chamber area. During the press connection, the circumference of the retaining element, i.e., its cutting ring and its support ring, decreases due to the pressure, with the tongue formed on the end face of one of the ends of its base body sliding further into the recess of the U-shaped recess formed at its other circumferential end.

[0015] The recess, with its parallel U-shaped legs, forms a guide for the tongue that slides into it.

[0016] Since the retaining element and thus the base body of its cutting ring are only connected to the inner surface of the connecting piece at specific points, the cutting ring can move in the circumferential direction while reducing its circumference and slide along the inner surface of the connecting piece and the outer surface of the pipe end section without the ends of the interrupted base body shifting axially relative to each other. The previously mentioned welded connection also prevents unwanted axial displacement of the entire retaining element and thus of the cutting ring when inserting the pipe end piece into the connecting piece.In addition, the spot welded joint, which remains intact during the pressing process to create the press connection, further secures the entire connection assembly against axial tensile forces, preventing the pipe end piece from being pulled out of the connecting piece or the press connection. Both measures thus contribute to, on the one hand, securing the cutting ring during the pressing process and thus securely protecting the sealing ring against the cutting elements of an axially shifting and / or deforming cutting ring, and, on the other hand, ensuring a highly reliable seal of the connection assembly.

[0017] The previously described process can be modified or further developed such that, after inserting the retaining element into the connecting piece, several spot welds are created, each connecting the support ring, the cutting ring, and the inner surface of the connecting piece. However, the procedure is preferably such that only one spot weld is created, which remains intact during the subsequent pressing process. The additional spot weld or additional spot welds, however, are designed such that they detach during the pressure applied during the creation of the press connection and due to the resulting radial movements (movements in the circumferential direction) of the cutting ring and the support ring.The appropriate quality of the spot welds can be achieved by dimensioning the contact pressure of the tongs used to create a particular spot weld and the welding current.

[0018] If the holding element is designed, as preferred, such that the interruptions present in the circumferential direction in the cutting ring and in the support ring partially overlap one another, the spot weld connection remaining during the pressing process is preferably produced at an end of the support ring delimiting the interruption, which end is projected beyond in the circumferential direction by an end of the cutting ring adjacent to the interruption in the base body.

[0019] The cutting ring is preferably made of a stainless steel with an austenitic microstructure that is initially unstable due to the alloying elements, but is already pre-strengthened prior to final production through the formation of deformation martensite. This microstructure is advantageously further strengthened during the creation of the press connection between the pipe end section and the connecting piece with the cutting ring arranged between them. The support ring can be made of the same material as the cutting ring, which promotes its secure connection to the retaining element. Furthermore, the cutting ring can have smoothed and / or chamfered edges on its side facing the sealing ring.In the unlikely event that the spot weld connection, which is designed as a permanent connection, comes loose during the creation of the press connection and the cutting ring moves and / or deforms in the axial direction up to the sealing ring, this can prevent possible damage to the sealing ring.

[0020] An example of the proposed connection arrangement will be presented and explained using drawings. The drawings show in detail: Fig. 1: a section of a connecting piece to be connected to a pipe end section in a press connection with an inserted retaining element and sealing ring, according to a possible embodiment, Fig. 2: a sectional view of a possible design of the connection arrangement, Fig. 3: the one for the holding element according to Fig. 1 cutting ring used, Fig. 4: the cutting ring according to Fig. 3 with inserted support ring

[0021] First of all, it should be noted that the representations shown in the individual figures do not necessarily correspond to each other in terms of their respective scale.

[0022] The Fig. 1 shows a section of a pipe end section 1 (see Fig. 2) in a press connection to be connected connecting piece 2 (for example a fitting) according to a possible embodiment. The figure shows the section of the respective connecting piece 2 with the inserted holding element 4, 5, 6 formed by a cutting ring 4, 5 firmly connected to a support ring 6 as well as with the inserted sealing ring 3. The arrangement of the individual rings within the connecting piece 2 is clearly visible. On the side facing away from the nozzle opening 15 and thus on the side facing the medium of the later inserted into the connecting piece 2 (see Fig. 2) and then the pipe end section 1 pressed together with it, the sealing ring 3 inserted into the connecting piece 2 is arranged.

[0023] The holding element 4, 5, 6 formed jointly by the cutting ring 4, 5 and the support ring 6 is arranged between the sealing ring 3 and an angled nozzle section 16 at the nozzle opening 15. The base body 4 of the cutting ring 4, 5 rests against the inside of the aforementioned angled nozzle section 16 of the connecting nozzle 2. The figure clearly shows that the tooth-like cutting elements 5 protrude from the base body 4 of the cutting ring 4, 5 on this side, which rests against the angled nozzle section 16 of the nozzle opening 15. They are directed towards the outer surface 13 of the pipe end section 1, which is still to be inserted into the connecting nozzle 2 via the nozzle opening 15 (see also Fig. 2) and inclined towards the sealing ring 3.

[0024] The Fig. Figure 2 shows a possible embodiment of the proposed connection arrangement in a sectional view in the still unpressed state with a section taken along its axial extent a. Essential components of the connection arrangement shown are a pipe end section 1, i.e., the end section of a pipe of a piping system not shown in its entirety here, a connecting piece 2 of another component (e.g., a fitting) of the said piping system connected to the pipe end section 1 (shown only partially, namely with its connecting piece 2), a sealing ring 3, and a retaining element 4, 5, 6 formed by connecting a cutting ring 4, 5 to a support ring 6.

[0025] A press connection is formed by the application of pressure between the pipe end section 1 and the connecting piece 2 of the further component to be connected to it, within which the sealing ring 3, the cutting ring 4, 5 and the support ring 6 are arranged, wherein the support ring 6 is inserted between the base body 4 and the cutting elements 5 of the cutting ring 4, 5 and is firmly connected to the cutting ring 4, 5. During the production of the press connection, tooth-like cutting elements 5 arranged on the circumference of the cutting ring 4, 5, i.e. in the circumferential direction u, press into the outer surface 13 of the pipe end section 1, thereby ensuring that the press connection between the pipe end section 1 and the connecting piece 2 of the further component is maintained even in the event of pull-out forces occurring in the axial direction a on the pipe end section 1 and / or the further component.

[0026] As can be seen from the illustration, starting from the front end of the pipe end section 1, which, during intended use of the arrangement, comes into contact with a medium conveyed through it, the sealing ring 3 is arranged first, followed by the cutting ring 4, 5 between it and a nozzle opening 15. They are arranged together in the chamber 7 by a corresponding shape of the connecting nozzle 2, thus eliminating the need for an intermediate ring between the sealing ring 3 and the cutting ring 4, 5 due to the special design of the cutting ring 4, 5.The lines shown on the circular cross-sectional area of ​​the sealing ring 3 shown in section do not represent a special border separating the sealing ring 3 from the cutting ring 4, 5, but rather the outer contour of the sealing ring 3 itself, which naturally continues behind the cutting surface and which is preferably (i.e. not necessarily) inserted into a bead formed on the inner circumferential surface 14 of the connecting piece 2.

[0027] In order to reliably counteract any pull-out forces that may occur in the arrangement and act in the axial direction a, the tooth-like cutting elements 5 formed on the cutting ring 4, 5 are arranged inclined in the direction of the outer circumferential surface 13 of the pipe end section 1 and simultaneously in the direction of the sealing ring 3. They protrude in a corresponding orientation from the base body 4 of the cutting ring 4, 5, with which the cutting ring 4, 5 rests against the inside of a nozzle section 16 of the nozzle opening 15 that is angled in the direction of the pipe end section 1 inserted into the connecting nozzle 2. In order to prevent the sealing ring 3 from being damaged by the cutting elements 5 of the cutting ring 4, 5 inclined in its direction when the press connection is created under the influence of pressure, these cutting elements 5 are formed on the circumference of the cutting ring 4, 5 on the side facing away from the sealing ring 3, as can be clearly seen in the figure.

[0028] The Fig. 3 shows again the connection piece 2 of the design according to the Fig. 1 inserted or in the connection arrangement according to the Fig. 2 used cutting ring 4, 5. This illustration clearly shows that the tooth-like cutting elements 5 arranged on the circumference of the cutting ring 4, 5 protrude on one side from a base body 4 of the cutting ring 4, 5. When inserting the cutting ring 4, 5 into the connecting piece 2 to be press-connected to the pipe end section 1, it is inserted into this connecting piece 2 in such a way that the said side of the base body 4 of the cutting ring 4, 5, from which the cutting elements 5 protrude, faces away from the sealing ring 3 previously inserted into the connecting piece 2.

[0029] The base body 4 of the cutting ring 4, 5 has an interruption 11 on its circumference. One of the ends of the base body 4 enclosing this interruption 11 has a tongue 8 extending from the end face of this end in the circumferential direction u. The other end of the base body 4 has a recess 9 extending from its end edge into the base body 4 in a U-shape. The legs of this U-shape, or the inner sides of the recess, are parallel to each other.

[0030] The Fig. 4 shows the Fig. 3 together with the support ring 6 arranged between the cutting elements 5 and the base body 4 of the cutting ring 4, 5. This support ring 6 counteracts deformation of the cutting ring 4, 5 during the formation of the press connection and additionally supports the effect of the cutting ring 4, 5 securing the connection arrangement against axial pull-out forces. The support ring 6 connected to the base body 4 of the cutting ring 4, 5 and the cutting ring 4, 5 form a common holding element 4, 5, 6. In order to insert this holding element 4, 5, 6 into the connecting piece 2 (see Fig. 1), both the cutting ring 4, 5 and the support ring 6 each have an interruption 11, 12 on their circumference (in the circumferential direction u) (cutting ring 4, 5 with interruption 11 and support ring 6 with interruption 12). This allows the rings to be easily pressed together for insertion into the connecting piece 2. The tongue 8 of the cutting ring 4, 5 then projects slightly into the recess 9 in the base body 4 of the cutting ring 4, 5. This prevents the ends adjacent to the interruption 11 of the cutting ring 4, 5 from axially shifting against one another when the press connection is created between the connecting piece 2 with inserted sealing ring 3 and holding element 4, 5, 6 and the pipe end section 1 inserted into the connecting piece 2.

[0031] The cutting ring 4, 5 and the support ring 6 are joined together in such a way that the aforementioned interruptions 11, 12 of both rings in the jointly formed holding element 4, 5, 6 are offset from each other with respect to the circumferential direction u, but are arranged partially overlapping each other. This is also shown in the Fig.1, which shows a section (a cut-out circumferential segment) of the connecting piece (2) to be joined to a pipe end section 1 in a press connection, with an inserted sealing ring 3 and retaining element 4, 5, 6, in a three-dimensional representation. During the creation of the press connection, the interruption 11 in the cutting ring 4, 5 and the interruption 12 in the support ring 6 are significantly reduced in size, almost to the point of being closed. In the process, the tongue 8 of the cutting ring 4, 5 slides further into the recess 9 of its base body 4. The tongue 8 and the recess 9 thus jointly form a guide. Because the interruptions 11, 12 of the cutting ring 4, 5 and the support ring 6 only partially overlap, the retaining element 4, 5, 6 is closed over its entire circumference. List of reference symbols 1 pipe end section 2 nozzles 3 Sealing ring 4, 5 Cutting ring with base body 4 and cutting elements 5 6 support ring 7th chamber 8 Tongue 9 Recess 10 spot weld connection 11 Interruption of the cutting ring 4, 5 12 Interruption of the support ring 6 13 outer surface of the pipe end section 1 14 inner surface of the nozzle 2 15 nozzle opening 16 angled nozzle section QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 5,108,134 A

[0005] EP 1 593 899 B1

[0007] DE 10 2022 115 161 A1

[0008]

Claims

[1] A connecting arrangement comprising a pipe end section (1) of a pipe and another component having a tubular connecting piece (2), between which a press connection exists, as well as comprising a sealing ring (3) and a holding element (4, 5, 6) comprising a cutting ring (4, 5), which, as further components of this press connection, are inserted into a chamber (7) formed between an outer circumferential surface (13) of the pipe end section (1) introduced into the connecting piece (2) via a piece opening (15) and an inner circumferential surface (14) of the connecting piece (2) whose cross-section is enlarged in this area, wherein the cutting ring (4, 5) arranged between the piece opening (15) and the sealing ring (3), with respect to the axial extension direction (a) of the connecting arrangement, consists of a base body (4) having an interruption (11) in the circumferential direction (u) and ofcutting elements (5) inclined against the axial direction of extension (a) and is firmly connected to the holding element (4, 5, 6) by a support ring (6) which is inserted between the base body (4) and the cutting elements (5) of the cutting ring (4, 5) and also has an interruption (12) in the circumferential direction (u), , characterized bythat within the press connection between the cutting ring (4, 5) with its cutting elements (5) arranged on the side facing away from the sealing ring (3) and inclined towards the sealing ring (3), and the support ring (6) forming the holding element (4, 5, 6) together with the cutting ring (4, 5), and the inner circumferential surface (14) of the connecting piece (2), there is a spot-welded connection (10), wherein on the cutting ring (4, 5), at the front edge of one of the ends enclosing the interruption (11) of its base body (4), a recess (9) is formed which extends in a U-shape with mutually parallel legs into the base body (4), and into which a tongue (8) projects, extending from the front edge of the other end of the base body (4) in the circumferential direction (u). [2] Connecting arrangement according to claim 1, characterized bythat the further component of the piping system, which is connected to the pipe end section (1) by means of its connecting piece (2) to form a press connection, is a fitting for connecting the pipe end section (1) to other components of the piping system. [3] Connecting arrangement according to claim 1 or 2, characterized by that a plurality of welding points are formed on the inner circumferential surface (14) of the connecting piece (2), on the support ring (6) and on the cutting ring (4, 5), but the support ring (6), the cutting ring (4, 5) and the inner circumferential surface (14) of the connecting piece (2) are only connected to one another by a spot weld connection (10) which is retained during the production of the press connection. [4] Connecting arrangement according to claim 3, wherein the interruptions (11, 12) on the circumference of the cutting ring (4, 5) and the support ring (6) in the holding element (4, 5, 6) partially overlap, characterized bythat the spot weld connection (10) which remains during the pressing process is formed on one of the ends of the support ring (6) enclosing the interruption (12), which end of the cutting ring (4, 5) projects beyond it in the circumferential direction (u) and is adjacent to the interruption (11) of the base body (4). [5] Connecting arrangement according to one of claims 1 to 4, characterized by that the cutting ring (4, 5) consists of a stainless steel with an austenitic structure which is initially unstable due to the alloying elements but which is already pre-strengthened before the final production of the cutting ring (4, 5) to form deformation martensite, this structure being further strengthened during the production of the press connection between the pipe end section (1) and the connecting piece (2) with the cutting ring (4, 5) arranged between them. [6] Connecting arrangement according to claim 1 or 5, characterized bythat the support ring (6) is made of the same material as the cutting ring (4, 5). [7] Connecting arrangement according to one of claims 1 to 6, characterized by that the cutting ring (4, 5) has smoothed and / or chamfered edges on its side facing the sealing ring (3).

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