Gas tight joint for a gas-insulated medium-voltage or high-voltage apparatus

Abstract

The present disclosure relates to a gas-tight joint (1) for a gas-insulated medium- or high-voltage apparatus, to the apparatus and to a method of producing and assembling the gas-tight joint. The gas-tight joint (1) comprises a conductor (2) comprising a first and second conductor portion (2a, 2b) arranged pivotable with respect to each other around a common central pivot point (r), a housing (3) comprising a first and second housing portion (3a, 3b) arranged pivotable with respect to each other around the common central pivot point (r), and a sealing mechanism (4) arranged between the first and second housing portion (3a, 3b) providing sealing therebetween in such a manner that a gas-escape path (L) between the first and second housing portion (3a, 3b) is sealed gas-tight at a plurality of possible orientations between the first and second housing portion (3a, 3b).

Description

[0001] GAS TIGHT JOINT FOR A GAS-INSULATED MEDIUM-VOLTAGE OR HIGH-VOLTAGE APPARATUS

[0002] FIELD OF THE DISCLOSURE

[0003] The present disclosure relates to the field of high-voltage and medium-voltage gas-insulated switchgear (GIS), gas-insulated busbars and gas-insulated lines (GIL). A compact and pivotable joint design comprised in gas-tight enclosure tubes is disclosed, which provides the possibility of free angular orientation of connecting tubes and at the same time gas-tight sealing for pressurized insulation gas contained therein. Furthermore, the present disclosure relates to a gas-insulated medium-voltage or high-voltage apparatus comprising such a joint, and to a method for producing and assembling a joint for gas-insulated medium- or high- voltage apparatuses comprising such a joint.

[0004] BACKGROUND OF THE DISCLOSURE

[0005] Gas-insulated switchgear and gas-insulated lines are built from several up to many hundreds of components, including a number of busbar tubes connected to each other. Each component has its own housing, which is connected to the adjacent housing by a flange. The connections by flanges must assure mechanical stability, gas-tightness and enclosure current flow. Thus, the flanges are typically pressed onto each other with a high force, which is applied by using several screw or bolt connections distributed around the circumference of the flanges. The screw connections may be screw-nut connections, or the screw may cooperate with a thread in the cooperating flange, or may be a bolt with two nuts. The screws and bolts are provided in respective holes in the flanges. Sufficient access to the bolts or screws on either side of the flange must be provided for fastening. As the housings act as pressure vessels, strict pressure vessel standards and tests apply which also vary for different countries.

[0006] A second known method for connecting housings specifically for high voltage gas-insulated lines is to weld them together. The housing ends are machined to allow a welding seam and are welded on-site to form long busbars or lines.

[0007] Welding of thin aluminum tubes on-site requires a specific circular welding process to achieve gas-tight and mechanically rigid connections in a constructionsite environment. Welded tubes cannot be disassembled in case of a failure or maintenance. The insulating spacers, which hold the center conductor concentrically inside the enclosure tube has to be specifically designed to fit into welded enclosures, because welded connections do not have the typical gap to hold the spacer between the bolted flanges.

[0008] In the known designs, the flanges have flat surfaces that are oriented vertically to the enclosure axis and are provided with a sealing that is axially compressed between the flanges. None of the known flanges provide any kind angular adjustability.

[0009] SUMMARY OF THE DISCLOSURE

[0010] Therefore, it is an object of the present disclosure to provide a gas-tight joint for a gas-insulated medium-voltage or high-voltage apparatus, in particular, which addresses the disadvantages of the conventional design, in particular of conventional enclosures or flanges. In particular, it is an object of the present disclosure to provide improved gas-tight joint for a gas-insulated medium-voltage or high- voltage apparatus, which is very compact, simple to assemble and disassemble and I or which enables free angular orientation between at least some parts of gas-tight enclosure for a gas-insulated medium-voltage or high-voltage apparatus. Further aspects of the disclosure are directed to a gas-insulated mediumvoltage or high-voltage apparatus comprising such a gas-tight joint and to a method for producing and assembling such a gas-tight joint.

[0011] These objects are achieved by the subject matter of the independent claims. Further advantageous embodiments and examples are explained with respect to the dependent claims, the description and the figures.

[0012] According to the present disclosure, a gas-tight joint for a gas-insulated mediumvoltage or high-voltage apparatus is specified. The gas-tight joint preferably comprises a conductor having a first conductor portion and a second conductor portion arranged pivotable with respect to each other around a common central pivot point. In other words, the first conductor portion and the second conductor portion are arrangable at any possible angular orientation with respect to each other, preferably within limits. The present disclosure enables that the angular orientation of the first conductor portion with respect to the second conductor portion does not affect the electrical current transfer from the first conductor portion to the second conductor portion. In other words, current transfer is enabled at any possible orientation. The first conductor portion may contact the second conductor portion for the required electric current transfer at any possible orientation, directly or indirectly.

[0013] The gas-tight joint further may comprise a housing, which surrounds radially the conductor, in particular the first conductor portion and the second conductor portion. The housing comprises a first housing portion and a second housing portion arranged pivotable with respect to each other around the common central pivot point. Thus, the first housing portion and / or the second housing portion are pivotable around the common or same or substantially same central pivot point similarly as the first conductor portion and the second conductor portion. It is therefore possible to orientate the conductor portions and the housing portions towards the same direction, i.e. to orientate each conductor portion and corresponding housing portion towards a same direction, such that the housing portions advantageously enclose the conductor for providing a surrounding insulation gas compartment. The angular orientation of the first housing portion with respect to the second housing portion does not affect the electrical current transfer from the first housing portion to the second housing portion. The current transfer is enabled at any possible orientation. The first housing portion may contact the second housing portion for the required electric current transfer at any possible orientation either via direct contact or via indirect contact.

[0014] The gas-tight joint further comprises a sealing mechanism arranged between the first housing portion and the second housing portion, wherein the sealing mechanism provides gas-tight sealing between the first housing portion and the second housing portion in such a manner that a gas-escape path between the first housing portion and the second housing portion is sealed gas-tight. The housing forms at least partially the insulation gas compartment of the gas-tight joint, at least in radial direction. It is required that the joint is sealed such that the gas within the gas compartment does not leak. In order to provide the required gas-tightness, a sealing mechanism is arranged in the gas-escape path between the first housing portion and the second housing portion. The sealing mechanism is configured to seal gas-tight at any possible orientation of the first housing portion with respect to the second housing portion. The sealing mechanism may therefore be called “dynamic sealing mechanism” enabling that the sealing seals gas-tight at a plurality or at any possible orientations of the gas-tight joint.

[0015] The gas-tight joint according to the present disclosure enables to connect adjacent arrange enclosure tubes and conductors, via the gas-tight joint, at a plurality of or at any possible orientations with respect to each other, in particular at any angular orientation with respect to each other in a horizontal plane and / or in a vertical plane. The gas-tight joint forms an adjustable connecting element for forming curves or bends in a gas-tight line in a simple and reliable manner. The major advantage of the gas-tight joint is that the angular orientation is, within limits, freely selectable without compromising regarding the required gas-tightness and I or installation space requirements. The gas-tight joint according to the present disclosure builds radially in particularly small compared to a conventional screwed flange design. In an embodiment, the gas-tight joint comprises a first spacer connecting the first conductor portion with the first housing portion and enabling synchronous movement of the first conductor portion and the first housing portion, and / or wherein the gas-tight joint comprises a second spacer connecting the second conductor portion with the second housing portion and enabling synchronous movement of the second conductor portion and the second housing portion. The spacer(s) is or are preferably arranged rigidly with respect to respective conductor portions and I or the respective housing portions, advantageously enabling the synchronous movement. The spacer(s) are e.g. arranged via form fit or press fit on the respective portions. The spacers may be held in axial positions by further parts, which axially contact the spacers. Further, the spacers may comprise openings enabling gas exchange. The spacers are further configured to provide and ensure the required positioning of the conductor with respect to the housing, in particular to ensure that the respective housing portion is arranged coaxially with respect to the respective conductor portion.

[0016] In a further embodiment, the first conductor portion and I or the second conductor portion comprise(s) a rounded contact surface, in particular a spherical contact surface, contacting the respective other conductor portion enabling electrical current transfer at a plurality of orientations between the first conductor portion and the second conductor portion. The contact surface has preferably its center point at the common central pivot point. The spherical contact surface advantageously provide the required contact between the first and second conductor portion at least at one contact circle. The rounded contact surface may follow at least partially the shape of a rounded cylinder, wherein the central axis (i.e. of the rounded cylinder) crosses the common central pivot point. In this embodiment, the first conductor portion and the second conductor portion may form a swivel joint. In the further embodiment, the respective conductor portion comprises the spherical contact surface, which may follow at least partially the shape of a sphere. The central point of the sphere lies in the common central pivot point, which enables the free rotation of the conductor portions. In this embodiment, the conductor portions form a ball joint.

[0017] It may be advantageous regarding ensuring contact when the first conductor portion comprises a first contact surface, in particular cylindrical or spherical contact surface, and when the second conductor portion comprises a corresponding second contact surface, in particular cylindrical or spherical contact surface, thereby providing an areal contact.

[0018] Assembling the conductor is realizable in a simple manner and an advantageous current transfer is realizable at the same time when the first conductor portion or the second conductor portion respectively comprises a cavity or opening axially extending into the respective conductor portion having a hollow cylindrical shape, wherein the other one of the conductor portions comprises an axially extending cylindrical stud like protrusion arranged at least partially in the opening, the axially extending cylindrical protrusion comprising a rounded or spherical contact surface contacting directly or indirectly the wall of the opening thereby enabling electrical current transfer at any possible orientation between the first conductor portion and the second conductor portion. The rounded or spherical contact surface may have a larger radius, or larger radial extension than the stud like protrusion, such that at least the spherical contact surface forms a bulge on the tip of the stud like protrusion. An advantageous mechanical guiding for guiding and for limiting the angular dis- placement / orientation between the conductor portions is realizable, when the conductor portion comprising the cavity has a rounded outer surface, in particular spherical outer surface, and the conductor comprising the protrusion has a mating rounded inner surface, in particular mating spherical inner surface, which extends along the outer surface. In particular, the central point of the spherical outer surface and the central point of the spherical inner surface lies in the common central pivot point. Alternatively in particular, a central axis of the rounded outer surface and a central axis of the rounded inner surface cross or intersect the common central pivot point. The thereby formed mechanical guiding contact enables that the two contacting portions can be moved advantageously around the predefined circular path as desired. Further, the stop can prohibit that the stud is moved too far into the cavity. Further, the rounded or spherical inner surface can enable that the cavity is, at any position of the first conductor portion with respect to the second conductor portion, covered by the inner surface thereby ensuring dielectric shielding of the otherwise exposed edges.

[0019] In a further embodiment, the radius of the outer surface to the radius of the inner surface of the first housing and I or second housing (i.e. of the gas-tight joint) have a ratio in a range from 1 :1 .5 to 1 :2.5, preferably have a ratio of 1 :2, for an advantageous dielectric shielding. In particular herein, the outer surface is a housing portion surface, and the inner surface is a conductor portion surface, and both surfaces delimit a gas-tight insulating space therebetween. The ratio of the radii of cylindrical portions of the gas-tight joint is preferably 1 / e +- 20%, more preferably 1 / e. The gas-tight joint can be according to the preceding embodiments, wherein the first housing portion and I or the second housing portion comprise(s) a rounded contact surface (i.e. housing contact surface), in particular a spherical contacting surface (i.e. housing contact surface), contacting the respective other housing portion enabling the gas-tight sealing between the first housing portion and the second housing portion at any possible orientation between the first housing portion and the second housing portion. The rounded contacting surface, which may follow at least partially the shape of a circular cylinder, forms in combination with the respective other housing portion a swivel joint. The spherical contacting surface, which may follow at least partially the shape of a sphere, forms in combination with the respective other housing portion a ball joint.

[0020] In a further embodiment, one of the housing portions comprises the rounded contact surface and the other housing portion comprises a mating shape, which enables that the housing portion comprising the rounded contact surface is insertable into the other housing portion until the predefined contact position. In case, one of the housing portions comprises a spherical contact surface, the other housing portion comprises a mating shape, e.g. a ring cylindrical shape extending axially, enabling that the spherical contact surface is insertable into the other housing portion until the predefined contact position.

[0021] The different housing portions are advantageously connectable when the gastight joint comprises a connecting mechanism, which surrounds at least partially the first housing portion and the second housing portion, and wherein the connecting mechanism further connects, in particularly rigidly in at least one direction, the first housing portion with the second housing portion. The connecting mechanism enables to connect the first housing portion with the second housing portion gas-tight at a plurality of orientations or at any possible orientation between the first housing portion and the second housing portion.

[0022] It is preferred, when the connecting mechanism comprises a connecting sleeve and a connecting bracket, wherein the connecting sleeve engages with the first housing portion and the connecting bracket engages with the second housing portion, and wherein the connecting bracket engages with the connecting sleeve for connecting the first housing portion with the second housing portion. The connecting bracket may have one or a plurality of radially extending protrusions, which correspond to depressions arranged in the connecting sleeve and / or the second housing portion. The protrusions engage with the depressions and form a form fit connection, thereby holding the first housing and the second housing in the selected orientation. The connecting sleeve may also have protrusions, which engage with respective depressions on the first housing portion. The orientation of the first housing portion with respect to the second housing portion may be determined by engaging the connecting sleeve with respective depressions.

[0023] An advantageous connection is realizable when the connecting sleeve surrounds at least partially the first housing portion and has a minimal radial extension, which is smaller than the maximal radial extension of the first housing portion thereby forming a form fit in one axial direction between the connecting sleeve and the first housing portion. The connecting sleeve is for example slideable on the first housing portion from one axial side, until it reaches an outer rounded or spherical surface of the first housing portion limiting the axial position of the connecting sleeve with respect to the first housing portion. The outer surface is for example a rounded or spherical surface having the center point in the common central pivot point. The connecting bracket may engage and thereby rigidly position the connecting sleeve such that the first housing portion and the second housing portions are arranged rigidly with respect to each other at a plurality of orientations or at any possible orientation.

[0024] In an embodiment, the connecting sleeve comprises a contact layer or contact element, preferably made of a material having advantageous gliding properties such as Polytetrafluorethylen PTFE or Teflon®. The contact element may be recessed in the connecting sleeve. The contact layer is configured to contact the outer surface of the first housing and to reduce friction resistance between the connecting sleeve and the first housing for an advantageous rotation of the first housing with respect to the connecting sleeve. In another embodiment, the outer housing may comprise such a contact layer of contact element.

[0025] In a further advantageous embodiment, at least one outer radius of the connecting sleeve, which at least partially defines the outer surface along which the connecting bracket extends, has the same dimension as the outer radius of the second housing portion along which the connecting bracket extends. In other words, the outer surface of the second housing and the outer surface of the connecting sleeve are at least partially arranged planar, and / or have at least partially the same radial dimensions. In this embodiment, the connecting bracket is advantageously arrangable, which reduces the required installation space. In an embodiment, the conductor comprises at least one conductor current transfer element arranged between the first conductor portion and the second conductor portion, preferably contacting the rounded I spherical contact surface, configured to enable current transfer between the first conductor portion and the second conductor portion at any possible orientation between the first conductor portion and the second conductor portion. The conductor current transfer element is for example a closed spiral spring, which electrically connects advantageously, due to its flexibility, the first conductor portion and the second conductor portion with each other, even when they are rotated with respect to each other. In a preferred embodiment, the conductor current transfer element is arranged in a respective depression or nut and extends beyond the depression or nut for contacting the respective conductor portions. It is preferred that the conductor comprises a plurality of conductor current transfer elements, each arranged in a respective depression or nut and contacting the respective surface of the conductor portions.

[0026] It is further advantageous, when the housing comprises at least one housing current transfer element arranged between the first housing portion and the second housing portion configured to enable current transfer between the first housing portion and the second housing portion at any possible orientation between the first housing portion and the second housing portion. The housing current transfer element may be a closed spiral spring preferably arranged in a respective depression or nut in one of the housing portions. The housing current transfer element is arranged such that it contacts the respective housing portion at a plurality of or at all possible orientations between the housing portions. A plurality of housing current transfer elements are also conceivable. In an embodiment, the sealing mechanism comprises two or more sealing rings, each being arranged in a respective sealing depression of the first housing portion or the second housing portion, forming in combination the sealing mechanism.

[0027] According to a further aspect of the present disclosure, a gas-tight apparatus for a gas-insulated medium-voltage or high-voltage apparatus is specified comprising the gas-tight joint as described above or hereinafter.

[0028] In an embodiment, the gas-insulated medium-voltage or high-voltage apparatus being selected from: gas-insulated switchgear (GIS), such as disconnectors, circuit breakers, covers, bushings, cable terminations, connection elements, busbar or other, and gas-insulated lines (GIL).

[0029] In a further embodiment, the gas-insulated medium-voltage of high-voltage apparatus comprising or consisting of gas-insulated components using a pressurized insulation gas selected from the group consisting of: air, N2, CO2, SFe, alternative synthetic insulation gases, and mixtures thereof.

[0030] In an embodiment, the gas-insulated medium-voltage of high-voltage apparatus may further comprise in addition one fixed or flexible connection portion, which connects via a flexible or non-flexible bracket one gas-tight joint tube to another enclosure tube.

[0031] In an embodiment, the apparatus further comprises a first enclosure tube and a second enclosure tube, the first enclosure tube being connected to the first housing portion of the gas-tight joint and the second enclosure tube being connected to the second housing portion of the gas-tight joint. The respective enclosure tubes may be connected to the first housing or second housing of the gas-tight joint via connecting portions, which may comprise a respective sealing, connecting brackets etc.. Further, the first conductor portion or the second conductor portion may be connected via a respective connection to a conductor of the enclosure tube enabling the required current transfer.

[0032] According to a further aspect of the present disclosure, a method of assembling the gas-tight joint, in particular a gas-tight joint as described above or hereinafter, for a gas-insulated medium-voltage or high-voltage apparatus is specified. The method may comprise the following method steps:

[0033] - Arranging a first conductor portion and a second conductor portion pivotable with respect to each other around a common central pivot point. The first conductor portion and the second conductor portion are preferably machined as desired and form in combination the centrally arranged conductor.

[0034] - Arranging a first housing portion and a second housing portion pivotable with respect to each other around the common central pivot point. The first housing portion and the second housing portion are preferably machined as desired and form in combination the radially outside arranged surrounding of the conductor.

[0035] Positioning the first conductor portion and the first housing portion with respect to the second conductor portion and the second housing portion at a desired orientation. The conductor and the housing, in particular its specific portions, are positioned as desired, for example at an angle of 10° with respect to each other, thereby forming a bend in the gas-tight enclosure line.

[0036] - Arranging a connecting mechanism at least partially around the first housing portion and the second housing portion for connecting the first housing portion and the second housing portion, in particular rigidly. The connecting mechanism holds the different parts of the gas tight joint in the predetermined position.

[0037] It is to be understood that both the foregoing general description and the following detailed description present embodiments with optional features and are intended to provide an overview or framework for understanding the nature and character of the disclosure. The accompanying drawings are included to provide a further understanding and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments and together with the description serve to explain in examples the principles and operation of the concepts disclosed.

[0038] BRIEF DESCRIPTION OF THE FIGURES

[0039] The herein described disclosure will be more fully understood from the detailed description given herein below and the accompanying drawings, which should not be considered to be limiting to the disclosure described in the appended claims. The drawings are showing in: Fig. 1 a side view of a gas-tight joint according to a first embodiment;

[0040] Fig. 2 a top view of the gas-tight joint according to the first embodiment;

[0041] Fig. 3 a front view of the gas-tight joint according to the first embodiment;

[0042] Fig. 4 a back view of the gas-tight joint according to the first embodiment; Fig. 5 a longitudinal section view as indicated in Fig. 1 via auxiliary line A of the gas-tight joint according to the first embodiment;

[0043] Fig. 6 a longitudinal section view as indicated in Fig. 2 via auxiliary line B of the gas-tight joint according to the first embodiment;

[0044] Fig. 7 a first detailed view as indicated in Fig. 5 via auxiliary line C of a con- necting mechanism of the gas-tight joint according to the first embodiment;

[0045] Fig. 8 a second detailed view as indicated in Fig. 6 via auxiliary line D of a conductor of the gas-tight joint according to the first embodiment;

[0046] Fig. 9 a third detailed view as indicated in Fig. 6 via auxiliary line E of a con- necting portion of an enclosure tube and the gas-tight joint according to the first embodiment. DETAILED DESCRIPTION OF THE FIGURES

[0047] Reference will now be made in detail to certain embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all features are shown. Embodiments disclosed herein may be embodied in many different forms and should not be construed as being limiting; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Whenever possible, like reference numbers will be used to refer to like components or parts.

[0048] Figure 1 shows a side view of a gas-tight joint 1 according to a first embodiment. The gas tight joint 1 may form part of a gas-tight apparatus 100 comprising further adjacent parts. The gas-tight joint 1 comprises a conductor 2 and a housing 3, which is arranged radially outside of the conductor 2. The gas-tight joint 1 extends in longitudinal direction z. The housing 3 comprises a first housing portion 3a and a second housing portion 3b arranged partially overlapping. The conductor 2 comprises a first conductor portion 2a and a second conductor portion 2b. The housing portions 3a, 3b and the conductor portions 2a, 2b are arranged pivotable with respect to each other around a common central pivot point r. In other words, the different portions of the housing 3 and the conductor 2 are arranged rotatable, within limits, with respect to each other such that a plurality of orientations between the different portions are enabled. It is therefore possible to orientate the different portions of the housing 3 and the conductor 3 relatively freely with respect to each other for forming e.g. curves or bends of the apparatus 100. In order to connect the axial ends of the gas-tight joint 1 with further parts of the gas-tight apparatus 100, connecting portions 103 are provided on an axial end of the housing portions 3a, 3b and on one axial end of the conductor portions 2a, 2b. Figure 1 further shows a connecting mechanism 6 configured to connect the first housing portion 3a with the second housing portion 3b. The connecting mechanism 6 comprises a connecting bracket 61 and a connecting sleeve 62. It is visible out of Figure 1 that the first housing 3a and the second housing 3b and the respective conductor portions 2a, 2b are not arranged coaxially with respect to each other, but are arranged at an angle with respect to each other.

[0049] Figure 2 shows the gas-tight joint 1 of Figure 1 from the top. Figure 2 in particular shows the angular orientation between the different portions of the gas-tight joint 1. Further, Figure 2 shows a bracket slit 61 a, which extends axially through the connecting bracket 61. The bracket slit 61 a may enable to advantageously arrange the connecting bracket 61 around the first housing portion 3a and the second housing portion 3b.

[0050] Figure 3 shows a front view of the gas-tight joint 1 . The view is perpendicular with respect to the longitudinal axis z of the second housing portion 3b and the second conductor portion 2b. Figure 3 further shows a spacer 5, in particular the first spacer 5a, which connects the first housing portion 3a with the first conductor portion 3b thereby holding the parts in position with respect to each other. The first spacer 5a comprises openings 51 enabling gas exchange from the gas compartment formed by the housing 3.

[0051] Figure 4 shows a back view of the gas-tight joint 1 . Figure 4 is very similar to

[0052] Figure 3 but shows the gas-tight joint 1 from the opposing direction. Figure 4 therefore shows advantageously the second spacer 5b, connecting the second housing portion 3b with the second conductor portion 2b.

[0053] Figure 5 shows a first longitudinal section view of the gas-tight joint 1 along the auxiliary line A as indicated in Figure 1 . Figure 5 advantageously shows the interior of the gas-tight joint 1 . Figure 5 shows the longitudinal axis z along which the first housing portion 3a and the first conductor portion 2a extend and along which the second housing portion 3b and the second conductor portion 2b extend. Additionally, Figure 5 shows advantageously the common central pivot point r around which the portions may be rotated. The spacers 5a, 5b connect the respective portions with each other. The spacers 5a, 5b may be rigidly arranged, for example by press fit or form fit on the respective conductor portion 2a, 2b and on the respective housing portion 3a, 3b, thereby enabling synchronous movement between the first portions 2a, 3a and the second portions 2b, 3b respectively. Figure 5 further advantageously shows the connecting mechanism 6. The connecting sleeve 62 is slid on the outer surface of the first housing portion 3a and connected to the connecting bracket 61 . The connecting bracket 61 comprises a radially inward extending protrusion at one axial end, which engages with a corresponding depression in the connecting sleeve 62. Further, on the other axial end of the connecting bracket 61 , a further radial inward extending protrusion is provided, which engages with a corresponding depression in the second housing portion 3b. Figure 5 further advantageously shows the spherical contact surface 30 of the first housing portion 3a and the spherical contact surface 30 of the second housing portion 3b. The spherical surface 30 of the second housing portion 3b transits into a circular cylindrical shape, which enables that the first housing portion 3a is insertable into the second housing portion 3b until the contact surfaces 30 contact each other. Figure 5 further indicates a sealing mechanism 4, which provides the gas-tight sealing between the first housing portion 3a and the second housing portion 3b. Figure 5 further indicates a detailed view via auxiliary line C. Figure 5 further indicates via respective connection portions 103 how the gas-tight joint 1 is connected to further parts of the gas-tight apparatus 100.

[0054] Figure 6 shows a second longitudinal section view of the gas-tight joint 1 along the section line B as shown in Figure 2. Figure 6 shows therefore a different orientation of the housing portions 3a, 3b and the conductor portion 2a, 2b with respect to each other without that the actual orientation differs with respect to Figure 5. The Figures 5 and 6 further advantageously shows that the gas-tight joint 1 forms a joint, in particular a ball joint, which enables to position the different portions freely. In another embodiment, the gas-tight joint 1 may form a swivel joint, in which the contact surfaces may have a rounded / circular surface with the respective axis being arranged coaxially and passing through the common central pivot point r. Figure 6 further indicates two further detailed views D and E indicated via respective auxiliary lines. The detailed views are explained with respect to the Figures 7 to 9 below.

[0055] Figure 7 shows a first detailed view as indicated in Figure 5 via auxiliary line C. Figure 7 advantageously shows the connecting mechanism 6 for connecting the first housing portion 3a with the second housing portion 3b at a plurality of orientations between the housing portions 3a, 3b. In order to enable this, the housing portions 3a, 3b comprise mating spherical contact surfaces 30, which overlap and which have the same common central pivot point. A rotation around the common central pivot point r does not affect the contact of the housing portions 3a, 3b. To connect the housing portions 3a, 3b at a plurality of possible orientations, the connecting mechanism 6 comprises the connecting bracket 61 and the connecting sleeve 62. The connecting sleeve 62 is slid over the first housing portion 3a from one axial end. In order to enable this, the minimal radial extension of the connecting sleeve 62 is larger than the maximum radial extension of the respective axial end of the first housing portion 3a. The other axial end of the first housing portion 3a, which contacts the second housing portion 3b has larger radial dimensions, which may follow the rounded or spherical contact surface 30, than the minimal radial extension of the connecting sleeve 62. The connecting sleeve 62 is therefore only slideable on the first housing portion 3a until a predefined maximum axial positon, preferably until it contacts the second housing portion 3b. Further, the connecting sleeve 62 may have a maximum radial extension, at least partially, which corresponds to the maximal radial extension of the adjacent portion of the second housing portion 3b, which enables to advantageously arrange the connecting bracket 61 on the housing 3. In other words, the connecting sleeve 62 and the second housing portion 3b may have the at least partially same radial extensions. The surface of the connecting sleeve 62, which contacts the first housing portion 3a, may also have a spherical shape following the shape of the contact surface 30. Further, the connecting sleeve 62 may comprise a contact element 62a, as shown in Figure 7, which is made for example made of PTFE, for friction reduction. The contact element 62a may also be a contact layer. The connecting sleeve 62 therefore enables to arrange the first housing portion 3a with respect to the second housing portion 3b at a plurality of orientations with respect to each other, preferably rigidly. According to this embodiment, the connecting sleeve 62 is connected to the second housing portion 3b via the connecting bracket 61 , which engages in respective depressions I nuts of the connecting sleeve 62 and the second housing portion 3b. In another embodiment, the connecting sleeve may be screwed onto the second housing element 3b, or may be arranged otherwise rigidly with respect to the second housing element 3b. The connecting bracket 62 has the advantage that it does not need a lot of radial installation space compared to a flanged screwed connection. Figure 7 further shows that the second spacer 5b contacts the second housing portion 3b and that the axial movement of the second spacer 5b is limited in one direction by a respective axial stop. Further parts, which may be arranged in the connecting portion 103, may position the second spacer 5b or the first spacer 5a rigidly as desired.

[0056] Figure 7 further shows the sealing mechanism 4, which is configured to form a gas-tight sealing in a gas-escape path L between the first housing portion 3a and the second housing portion 3b. The sealing mechanism 4 comprises one sealing ring 40, which is arranged in a sealing groove 41 in the first housing portion 3a. Arranging the sealing ring 40 in a sealing groove 40 of the second housing or a combination thereof would also be possible. In a further embodiment, the sealing mechanism comprises a plurality of sealing rings 40, in particular arranged in respective grooves. The sealing ring 40 may be an O-ring or X-ring having a plurality of sealing lips.

[0057] Figure 7 further shows a housing current transfer element 8, preferably in the form of a closed spiral spring, which is configured to contact both housing portions 3a, 3b for enabling current transfer between the housing portions 3a, 3b. The current transfer element 8 is arranged in a respective groove or depression 70 and extends beyond the respective groove 70 for contacting both portions 3a, 3b, similarly as the sealing ring 40.

[0058] In a further embodiment, not shown in the figures, the housing portions 3a, 3b may comprise a sealable opening, which extends into a sealing room formed between the housing portions 3a, 3b and two sealing rings 40. The sealable opening may be used to perform a leakage test of the sealing mechanism 4 comprising two sealing rings.

[0059] Figure 8 shows a second detailed view in particular of the conductor 2 of the gastight joint 1 as indicated in Fig. 6 via auxiliary line D. The conductor 2 comprises the first conductor portion 2a and the second conductor portion 2b. Both conductor portions 2a, 2b are connected to respective housing portions 3a, 3b via the spacers 5a, 5b. The conductor portions 2a, 2b may enable that the spacers 5a, 5b are slid onto the conductor portions 2a, 2b until they reach an axial stop. The spacers 5a, 5b may be arranged rigidly for example via press fit or form fit onto the respective conductor portions 2a, 2b. The first conductor portion 2a comprises a stud like protrusion 24 with a rounded contact surface 241 or stud contact surface 241 at the tip of the stud like protrusion 24. The rounded contact surface 241 forms a bulge at the tip of the protrusion 24 having a larger radial extension than the rest of the stud like protrusion 24. The center point of the rounded contact surface 241 is arranged at the common central pivot point r. The stud like protrusion 24 may have a circular cylindrical shape with the bulge at its tip. The second conductor portion 2b has a cavity 23 or an opening 23, in the shape of a circular cylinder. The stud like protrusion 24 is arranged in the cavity 23. The spherical contact surface 241 contacts the wall of the cavity 23, in particular via conductor current transfer elements 7, which are arranged between the first conductor portion 2a and the second conductor portion 2b, contacting both and thereby enabling the current transfer. The conductor current transfer elements 7 are arranged in respective conductor current transfer element depressions or nuts 70. Figure 8 shows that only the spherical contact surface 241 would contact the wall of the cavity 23 in case both conductor portions 2a, 2b are arranged coaxially. The beginning of the cavity 23 forms in combination with the beginning of the stud like protrusion 24 a stop, which determines the limits of the angular movement between the first conductor portion 2a and the second conductor portion 2b.

[0060] The first conductor portion 2a further comprises a bulge, having a spherical inner surface 22 or inner guiding contact surface 22, which extends beyond a spherical outer surface 21 or outer guiding contact surface 21 of the second conductor portion 2b. The spherical inner surface 22 and the spherical outer surface 21 , which have their center point lying on the common central pivot point r, correspond with each other and form an axial gliding surface, determining in combination the possible orientations of the first conductor portion 2a with respect to the second conductor portion 2b. The axial gliding surface also functions as an axial stop determining the maximum possible insert position of the stud like protrusion 24 into the cavity 23. This is also visible in Figure 8, because the tip of the protrusion 24 does not contact the bottom of the cavity 23.

[0061] Figure 9 shows a third detailed view of the gas-tight joint 1 , in particular of the connecting portion 103, as indicated in Fig. 6 via auxiliary line E. The connecting portion 103 is configured to connect the axial ends of the gas-tight joint 1 to further parts of the gas-tight apparatus 100, in particular to the first enclosure tube 101 and the second enclosure tube 102 (not shown in the figures). The connecting portion 103 may comprise a bracket, which connects overlapping portions of the respective housing portion 3a, 3b and the respective enclosure tube 101 , 102.

[0062] The connecting portion 103 may further comprise a sealing element (not shown), in particular a plurality of sealing rings, arranged preferably in respecting depressions for providing a gas-tight sealing. The connecting portion 103 may further comprise parts (not shown), which connect the respective conductor portions 2a, 2b mechanically and electrically with respective conductor parts of the adjacent parts of the gas-tight apparatus 100. Figure 6 shows respective current transfer elements arranged in nuts at the outer axial ends of the respective conductor portions 2a, 2b.

[0063] Many parts of the gas-tight joint 1 , in particular the housing portions 3a, 3b, and the spacers 5a, 5b have specific radii for dielectric stress relief, in particular at triple points, best visible in Figure 7.

[0064] LIST OF REFERENCE SIGNS

[0065] 100 gas-tight apparatus 5 spacer

[0066] 1 gas-tight joint 5a first spacer

[0067] 2 conductor 30 5b second spacer

[0068] 2a first conductor portion 51 spacer openings

[0069] 2b second conductor portion 6 connecting mechanism

[0070] 20 rounded / spherical contact 61 connecting bracket surface 61 a bracket slit

[0071] 21 rounded / spherical outer sur35 62 connecting sleeve face, outer guiding contact

[0072] 62a contact element surface

[0073] 7 conductor current transfer

[0074] 22 rounded / spherical inner surelement face, mating inner guiding

[0075] 70 conductor current transfer contact surface

[0076] 40 element groove

[0077] 23 cavity, opening

[0078] 8 housing current transfer

[0079] 24 stud like protrusion element

[0080] 241 rounded / spherical contact

[0081] 80 housing current transfer surface, stud contact surface element groove

[0082] 3 housing

[0083] 45 101 first enclosure tube

[0084] 3a first housing portion

[0085] 102 second enclosure tube

[0086] 3b second housing portion

[0087] 103 connecting portion

[0088] 30 rounded / spherical contact

[0089] L gas-escape path surface, housing portion conz longitudinal axis tact surface

[0090] 50 r common central pivot point I

[0091] 4 sealing mechanism point of rotation

[0092] 40 sealing ring

[0093] 41 sealing groove / depression

Claims

PATENT CLAIMS1 . Gas-tight joint (1 ) for a gas-insulated medium-voltage or high-voltage apparatus (100) comprising: a. a conductor (2) comprising a first conductor portion (2a) and a second conductor portion (2b) arranged pivotable with respect to each other around a common central pivot point (r); b. a housing (3), which surrounds radially the conductor (2), the housing (3) comprising a first housing portion (3a) and a second housing portion (3b) arranged pivotable with respect to each other around the common central pivot point (r); and c. a sealing mechanism (4) arranged between the first housing portion (3a) and the second housing portion (3b), wherein the sealing mechanism (4) provides sealing between the first housing portion (3a) and the second housing portion (3b) in such a manner that a gas-escape path (L) between the first housing portion (3a) and the second housing portion (3b) is sealed gas-tight at a plurality of possible orientations between the first housing portion (3a) and the second housing portion (3b).

2. The gas-tight joint (1 ) according to claim 1 , wherein the gas-tight joint (1 ) comprises a first spacer (5a) connecting the first conductor portion (2a) with the first housing portion (3a) and enabling synchronous movement of the first conductor portion (2a) and the first housing portion (3a), and / or whereinthe gas-tight joint (1 ) comprises a second spacer (5b) connecting the second conductor portion (2b) with the second housing portion (3b) and enabling synchronous movement of the second conductor portion (2) and the second housing portion (3b).

3. The gas-tight joint (1 ) according to any one of the preceding claims, wherein the first conductor portion (2a) and I or the second conductor portion (b) comprise(s) a rounded contact surface (20), in particular a spherical contact surface (20), contacting the respective other conductor portion (2a, 2b) enabling electrical current transfer, in particular via at least one conductor current transfer element (7) at a plurality of orientations between the first conductor portion (2a) and the second conductor portion (2b).

4. The gas-tight joint (1 ) according to any one of the preceding claims, wherein the first conductor portion (2a) or the second conductor portion (2b) comprises a cavity (23) axially extending into the respective conductor portion (2a, 2b) having a hollow cylindrical shape, wherein the other one of the conductor portions (2a, 2b) comprises an axially extending cylindrical stud like protrusion (24) arranged at least partially in the cavity (23), the axially extending cylindrical stud like protrusion (24) comprising a rounded contact surface (241 ), in particular a spherical contact surface (241 ), contacting the wall of the cavity (23) thereby enabling electrical current transfer at a plurality of orientations between the first conductor portion (2a) and the second conductor portion (2b).

5. The gas-tight joint (1 ) according to claim 4, wherein the conductor portion (2b) comprising the cavity (23) has a rounded outer surface (21 ), in particular spherical outer surface (21 ), and the conductor portion (2a) comprising the protrusion (24) has a mating rounded inner surface (22), in particular mating spherical surface (22), which extends along the outer surface (21 ); in particular wherein a central point of the outer surface (21 ) and a central point of the inner surface (22) lies in the common central pivot point (r), thereby forming a mechanical guiding contact at a plurality of orientations between the first conductor portion (2a) and the second conductor portion (2b).

6. The gas-tight joint (1 ) according to any one of the preceding claims, wherein the first housing portion (3a) and I or the second housing portion (3b) comprise^) a rounded contact surface (30), in particular a spherical contact surface (30), contacting the respective other housing portion (3a, 3b) and enabling the gas-tight sealing between the first housing portion (3a) and the second housing portion (3b) at a plurality of orientations between the first housing portion (3a) and the second housing portion (3b).

7. The gas-tight joint (1 ) according to any one of the preceding claims, wherein the gas-tight joint (1 ) comprises a connecting mechanism (6) surrounding at least partially and connecting the first housing portion (3a) and the second housing portion (3b), thereby enabling to connect the first housing portion (3a) with the second housing portion (3b) gas-tight at a plurality of orientations between the first housing portion (3a) and the second housing portion8. The gas-tight joint (1 ) according to claim 7, wherein the connecting mechanism (6) comprises a connecting sleeve (62) and a connecting bracket (61 ), wherein the connecting sleeve (62) engages with the first housing portion (3a) and the connecting bracket (61 ) engages with the second housing portion (3b) and with the connecting sleeve (62) for connecting the first housing portion (3a) with the second housing portion (3b).

9. The gas-tight joint (1 ) according to claim 8, wherein the connecting sleeve (62) surrounds at least partially the first housing portion (3a) and has a minimal radial extension, which is smaller than the maximal radial extension of the first housing portion (3a) thereby forming a form fit in one axial direction between the connecting sleeve (62) and the first housing portion (3a).

10. The gas-tight joint (1 ) according to any one of the preceding claims, wherein the conductor (2) comprises at least one conductor current transfer element (7) arranged between the first conductor portion (2a) and the second conductor portion (2b), preferably contacting the spherical contact surface (20), configured to enable current transfer between the first conductor portion (2a) and the second conductor portion (2b) at any possible orientation between the first conductor portion (2a) and the second conductor portion (2b).1 1 . The gas-tight joint (1 ) according to any one of the preceding claims, wherein the housing (3) comprises at least one housing current transfer element (8) arranged between the first housing portion (3a) and the second housing portion (3b) and configured to enable current transfer between the first housing portion (3a) and the second housing portion (3b) at any possibleorientation between the first housing portion (3a) and the second housing portion (3b).

12. The gas-tight joint (1 ) according to any one of the preceding claims, wherein the sealing mechanism (4) comprises one or more sealing rings (40), preferably O-rings or X-rings, each being arranged in a respective sealing depression (41 ) of the first housing portion (3a) or the second housing portion (3b), forming in combination the sealing mechanism (4).

13. Gas-tight apparatus (100) for a gas-insulated medium-voltage or high-voltage apparatus comprising the gas-tight joint (1 ) according to any one of the preceding claims.

14. The gas-tight apparatus (100) according to claim 13, further comprising a first enclosure tube (101 ) and a second enclosure tube (102), the first enclosure tube (101 ) being connected to the first housing portion (3a) and the second enclosure tube (102) being connected to the second housing portion (3b).

15. Method of assembling the gas-tight joint (1 ), in particular a gas-tight joint (1 ) according to any one of the preceding claims 1 to 12, for a gas-insulated medium-voltage or high-voltage apparatus, comprising the method steps of: a. arranging a first conductor portion (2a) and a second conductor por- tion (2b) pivotable with respect to each other around a common central pivot point (r);b. arranging a first housing portion (3a) and a second housing portion (3b) pivotable with respect to each other around the common central pivot point (r); c. positioning the first conductor portion (2a) and the first housing portion (3a) with respect to the second conductor portion (2b) and the second housing portion (3b) at a desired orientation; and d. arranging a connecting mechanism (6) at least partially around the first housing portion (3a) and the second housing portion (3b) for connecting the first housing portion (3a) and the second housing portion (3b), in particular rigidly.

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