Device for connecting two pipe sections

Abstract

Device for connecting two pipe sections, comprising - a connecting body (1, 7) through which a cylindrical bore (11, 71) is guided, which transitions at both ends into an outwardly widening conical bore (12, 72), - two union nuts (2), each having a bore (21) for receiving a pipe section (5, 6), which are provided with an internal thread (22) with which they can be screwed onto an external thread (13) arranged at each end on the connecting body (1, 7) and which, following the internal thread (22), have a shoulder (23) which is preferably conical and tapers in the opposite direction to the conical bore of the connecting body, - two cutting rings (3) which are arranged in the bore (21) of a union nut (2) and which have a bore for passing a pipe section (5, 6) and a cutting element (33) having at least one cutting edge, which faces a pipe section (5, 6) passing through the bore and which, in the state of the union nut (2) being screwed onto the connecting body (1, 7), projects into the conical bore (12, 72) of the connecting body (1, 7), wherein at least one radially circumferential groove (16, 74) is arranged in the cylindrical bore (11, 71) of the connecting body (1, 7), in which a sealing ring (4) is arranged for sealing against a pipe section (5, 6) inserted into the bore (11, 71).

Description

[0001] The invention relates to a device for connecting two pipe sections according to claim 1.

[0002] During the manufacture of railway carriages, long pipelines are installed both beneath and within the carriages to supply and distribute fluids to the braking, air conditioning, and hydraulic systems within a train. Due to the considerable length of the carriages and the lengths and complex configurations of the pipeline components, a common problem arises when installing the final section of the pipeline: the pipe ends are often too long or too short. This necessitates time-consuming and error-prone individual adjustments. The length of the final pipe section is measured and cut accordingly. If the cut pipe section does not fit perfectly, leaks can occur, which are either very difficult to repair or may only become apparent later during operation, potentially leading to consequential damage.

[0003] Currently, so-called VEBEO fittings, also known as compression fittings, are regularly used to join pipe sections, as described, for example, in the "Knorr-Bremse Handbook for Rail Vehicles," 1976 edition. This fitting comprises a connecting sleeve with external threads at both ends, the through-bore of which transitions via a shoulder at each end into a conically widening bore, and two union nuts, each accommodating a steel ring, a washer, and a sealing ring. The two union nuts each have a conical bore that tapers in the opposite direction to the conical bore of the connecting sleeve.

[0004] The pipe sections to be joined are inserted into the connecting sleeve from both sides through the bore of each union nut. The union nuts are then screwed onto the connecting sleeve and tightened. This presses the sealing ring into the conical bore against the shoulder, thus holding it axially between the shoulder and the washer. The steel ring rests in the conical bore of the union nut and is pressed both axially against the washer and radially against the pipe section. An illustration of a VEBEO fitting from the Knorr-Bremse Rail Vehicle Handbook is included in... Fig. 1 reproduced.

[0005] A disadvantage of the previously known device is that it only allows for limited compensation of length tolerances. This is where the present invention comes in. The invention is based on the objective of creating a device for connecting two pipe sections, in particular for the production of a hydraulic or pneumatic pipeline, which enables improved compensation of length tolerances between the two pipe sections to be joined. According to the invention, this objective is achieved by a device with the features of claim 1.

[0006] The invention provides a device for connecting two pipe sections, particularly for constructing a hydraulic or pneumatic pipeline, which enables improved compensation for length tolerances between the two pipe sections to be joined. Each union nut incorporates a cutting ring with a conical section that, when the union nut is screwed onto the connecting body, projects into the conical bore of the connecting body and has a cutting element with at least one cutting edge. This creates a connection between the cutting ring and the pipe section, even with differing distances between the two pipe sections, resulting in axial fixation and a metallic seal. The pipe section is fixed in its current position by the cutting ring cutting into the pipe section and by the slight pipe deformation that occurs depending on the pipe section's wall thickness.The connection is sealed by the preload of the cutting ring, ensuring the tightness of the metallic seal. The circumferential groove in the bore, incorporated into the sealing ring, provides an additional soft seal, thus ensuring further sealing reliability.

[0007] In a further development of the invention, a diameter-reduced section is provided at a first end of the cylindrical bore of the connecting body, spaced apart from the conical bore. This section forms a stop for an inserted pipe section. This allows for a defined positioning of the pipe section within the connecting body. After securing this pipe section in the connecting body, the connecting body can be slid onto the second pipe section. Subsequently, the connecting body can be positioned as desired to achieve the necessary length compensation. It is then secured by screwing the associated union nut onto the connecting body, causing the cutting ring to engage with the outer surface of the pipe section and create a metallic seal.By designing the cutting ring as a metal- and soft-sealing cutting ring, a metallic and soft-sealing seal between the cutting ring and the pipe section can be achieved.

[0008] The circumferential groove in the bore, into which the sealing ring is inserted, is preferably positioned opposite the stop, close to the external thread of the connecting body. This ensures a soft seal regardless of how the second pipe section is positioned in the connecting body. Even in the event of unplanned pipe joints that cause the pipe section to slide within the bore of the connecting body, this sealing ring eliminates the risk of leakage.

[0009] In one embodiment of the invention, the connecting body is designed with an enlarged outer diameter in the area of ​​the at least one groove. This results in an increased wall thickness, thus ensuring sufficient wall thickness even within the groove.

[0010] In a further embodiment of the invention, the connecting body preferably has a radially circumferential rib or groove on its outer surface, at least in a central section. This provides orientation for the longitudinal position of a pipe section. This ensures, for example, that the pipe section functions correctly when positioned at a defined distance on both sides of this rib. Instead of the rib, a circumferential groove or other marking, at least in some areas, can also be provided.

[0011] Other embodiments and configurations of the invention are specified in the remaining dependent claims. An exemplary embodiment of the invention is illustrated in the drawings and is described in detail below. The drawings show: Fig. 1: the illustration of a VEBEO screw connection according to the state of the art (from: Knorr-Bremse Handbook Rail Vehicles", edition 1976); Fig. 2: the schematic representation of a connection arrangement of two pipe sections; Fig. 3: the detailed representation of section A of the connection arrangement from Fig. 1 and Fig. 4: the detailed representation of section B of the connection arrangement from Fig. 1. Fig. 5: the schematic representation of a connection arrangement of two pipe sections in a further embodiment; Fig. 6: the detailed representation of the connection arrangement from Fig. 5 a) in section A; b) in section B.

[0012] The device chosen as an exemplary embodiment for connecting two pipe sections essentially consists of a connecting body 1, two identically designed union nuts 2 and two identically designed cutting rings 3.

[0013] The connecting body 1 is essentially hollow and cylindrical and has a through bore 11 that transitions at both ends into an outwardly widening conical bore 12. The connecting body 1 is provided with an external thread 13 at both ends. At one end, the through bore has a reduced-diameter section 14 spaced apart from the conical bore 12, forming a shoulder 15. At its other end, the through bore 11 has a radially circumferential groove 16 spaced apart from the conical bore 12, into which a sealing ring 4 is inserted. In the exemplary embodiment, the sealing ring is designed as a lip seal. Of course, the use of other sealing rings known in the prior art, for example an O-ring, is also possible.On the outside, the connecting body 1 has an area 17 with an increased outer diameter in the area of ​​the circumferential groove 16, which increases the material thickness of the connecting body 1 in this area.

[0014] In the exemplary embodiment, the union nut 2 is designed as a hexagonal nut and has a cylindrical bore 21, which is provided with an internal thread 22 for screwing onto an external thread 13 of the connecting body 1. Adjoining the internal thread 22 is a shoulder 23 that tapers in the opposite direction to the conical bore 12 of the connecting body 1.

[0015] The cutting ring 3 is essentially hollow cylindrical and has a wedge-shaped side wall 31 at one end. The inclination of the wedge-shaped side wall 31 corresponds essentially to the inclination of the conically tapered shoulder 23 of the union nut 2. On its side opposite the side wall 31, the cutting ring 3 has a diameter-reduced section 32, to which a cutting element 33, inclined in the direction of the rotational axis of the cutting ring 3 and having at least one cutting edge, is attached.

[0016] In Fig. Figure 2 shows a connection arrangement of two pipe sections 5, 6 with such a device. A first pipe section 5 is inserted through the bore 21 of a union nut 2 and the cutting ring 3 received by it into the through bore 11 of the connecting body, where it rests against the shoulder 15 formed by the diameter-reduced section 14. The union nut 2 is screwed onto the external thread 13 of the connecting body 1 with its internal thread 22.

[0017] When the union nut 2 is screwed onto the external thread 13 of the connecting body 1, the cutting ring 3, which bears against the shoulder 23 of the union nut 2 with its wedge-shaped side wall 31, is displaced axially towards the connecting body 1, whereby its cutting element 33 is guided along the conical bore 14 of the connecting body 1 in the direction of the first pipe section 5 and cuts into its outer surface, thereby achieving a metal-to-metal sealing seal (see figure). Fig. 4).

[0018] The second pipe section 6 is inserted on the opposite side of the connecting body 1 through the bore 21 of a second union nut 2 and the cutting ring 3 received by it into the through-bore 11 of the connecting body, through the sealing ring 4 received by the groove 16, until the desired length compensation is achieved, i.e., until the desired total pipe length is reached. In this position, the second union nut 2 is screwed with its internal thread 22 onto the external thread 13 of the connecting body 1 facing it.

[0019] When the second union nut 2 is screwed onto the external thread 13 of the connecting body 1, the cutting ring 3, which bears against the shoulder 23 of the union nut 2 with its wedge-shaped side wall 31, is again displaced axially towards the connecting body 1. This causes its cutting element 33 to cut into the outer surface of the second pipe section 5 along the conical bore 14 of the connecting body 1, thus creating a metal-to-metal seal. Additionally, a soft seal is provided by the sealing ring 4 received by the groove 16 (see figure). Fig. 3).

[0020] In the exemplary embodiment according to Fig. 5 is a connecting body 7, which is essentially hollow cylindrical and has a through bore 71 that transitions at both ends into an outwardly widening conical bore 72. The connecting body 7 is also provided with an external thread 73 at both ends. In contrast to the previously described embodiment, however, there is no diameter-reduced section forming a shoulder.

[0021] The connecting body 7, on the other hand, has a radially circumferential groove 74 at both ends in the through-bore 71, spaced apart from the respective conical bore 72. A sealing ring 4 is inserted into each of these grooves; in this case, the sealing ring is designed as a lip seal. Compared to the previously described embodiment, the connecting body 7 has a larger outer diameter for the same inner diameter, thus increasing the material thickness of the connecting body 7. A circumferential groove 75 is provided in the center of the connecting body, forming a guide for the longitudinal position of a pipe section.

[0022] The first pipe section 5 and the second pipe section 6 are each inserted into the through-bore 71 of the connecting body 7 on opposite sides through the bore 21 of a union nut 2 and the cutting ring 3 received by the union nut. The sealing ring 4, which is received by the groove 74 on each side, is inserted until the desired length compensation is achieved, i.e., until the desired total pipe length is reached. In this position, the two union nuts 2 are screwed with their internal thread 22 onto the external thread 73 of the connecting body 7 facing them. The connecting body 7 of this embodiment thus allows axial length adjustment of both pipe sections 5 and 6 within the through-bore 71.

[0023] When the union nuts 2 are screwed onto the respective external thread 73 of the connecting body 7, the respective cutting ring 3, with its wedge-shaped side wall 31 bearing against the shoulder 23 of the union nut 2, is displaced axially towards the connecting body 7. This causes its cutting element 33 to cut into the outer surface of the respective pipe section 5, 6 along the respective conical bore 72 of the connecting body 7 in the direction of the groove 75, thus creating a metal-to-metal seal. Additionally, the sealing rings 4, which are received by the grooves 74, provide a soft seal (see figure). Fig. 6).

Claims

[1] Device for connecting two pipe sections, comprising - a connecting body (1, 7) through which a cylindrical bore (11, 71) is guided, which at both ends merges into an outwardly widening conical bore (12, 72), - two union nuts (2), each having a bore (21) for receiving a pipe section (5, 6), which are provided with an internal thread (22) with which they can be screwed onto an external thread (13) arranged at the end of the connecting body (1, 7) and which, following the internal thread (22), has a shoulder (23) which is preferably conical and tapers in the opposite direction to the conical bore of the connecting body, - two cutting rings (3), each of which is arranged in the bore (21) of a union nut (2) and which has a bore for the passage of a pipe section (5, 6) and a cutting element (33) which has at least one cutting edge and which faces a pipe section (5, 6) passed through the bore and which, when the union nut (2) is screwed onto the connecting body (1, 7), projects into the conical bore (12, 72) of the connecting body (1, 7), wherein at least one radially circumferential groove (16, 74) is arranged in the cylindrical bore (11, 71) of the connecting body (1, 7), in which groove a sealing ring (4) is arranged for sealing against a pipe section (5, 6) introduced into the bore (11, 71). [2] Device according to claim 1, characterized bythat in the cylindrical bore (11) of the connecting body (1) at a first end spaced from the conical bore (12) there is a section (14) of reduced diameter, by means of which a stop for a pipe section to be inserted is formed. [3] Device according to claim 1 or 2, characterized by that the connecting body (1, 7) is designed with an enlarged outer diameter in the region of the at least one groove (16, 74). [4] Device according to one of the preceding claims, characterized by that the connecting body (1, 7) has, on the outside, preferably in a central section, a web or a groove (75) which runs radially around at least some areas. [5] Connecting arrangement, comprising two preferably metallic pipe sections (5, 6) which are connected to one another via a device according to one of the preceding claims, wherein in each case a pipe section (5, 6) is introduced through the bore (21) of a union nut (2) and the cutting ring (3) received thereby into the cylindrical bore (11, 71) of the connecting body (1, 7), and wherein the union nuts (2) are screwed onto the connecting body (1, 7) on both sides of the latter, as a result of which the cutting rings (3) with their cutting element (33) are each pressed axially into a conical bore (12, 72), as a result of which the cutting element (33) of the two cutting rings (3) is introduced into the outer casing layer of the respectively received pipe section (5, 6) in a cutting and sealing manner. [6] Connecting arrangement according to claim 5, characterized bythat in the cylindrical bore (11) of the connecting body (1) at a first end spaced from the conical bore (12) there is a section (14) of reduced diameter, by means of which a stop is formed, against which one of the pipe sections (5) rests, wherein the second pipe section (6) projects deeper into the cylindrical bore (11) of the connecting body (1) than the first pipe section (5) and wherein at least the second pipe section (6) is additionally sealed off from the connecting body (1) by a sealing ring (4) arranged in the radial groove (16) of the bore (11).

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