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

Abstract

The present disclosure relates to gas-tight enclosures for a gas-insulated me- diumvoltage or high-voltage apparatus, to the apparatus and to a method of producing and assembling the gas-tight enclosure. The gas-tight enclosure comprising a connection portion arranged between a first enclosure tube and a second enclosure tube for providing a gas-tight connection. The connection portion comprising a flexible spring bracket connecting the first end and the second end and enabling limited spring loaded movement between the first end and the second end, and a dynamic sealing element arranged between the first end and the second end and providing dynamic sealing between the first end and the second end in such a manner that a gas-escape path between the first end and the second end is sealed in gas-tight manner.

Description

[0001] GAS TIGHT ENCLOSURE FOR A GAS-INSULATED MEDIUM-VO- LATAGE 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 flange design comprised in gas-tight enclosure tubes is disclosed, which provides a limited spring loaded moveable mechanical connection and gas 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 connection, and to a method for producing and assembling an enclosure for gas-insulated medium- or high-voltage apparatuses comprising such a connection.

[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. However, welded connections require less radial space than flanges, provide life-long sealing and require fewer parts for assembly by avoiding separate flanges, bolts, washers and nuts. 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] EP1058363A1 , first published on 06.12.2000 in the name of Siemens AG, discloses a welded and releasable flange connection for the metallic enclosure of a gas-insulated system. Two connecting flanges are welded onto the ends of two different enclosure portions. The vertical flat faces of the flanges are then bolted together by a number of axial bolts or screws distributed along the circumference of the enclosure to provide a gas-tight connection. Thus, for assembly or disassembly of housings, all bolts, nuts and washers must be tightened or loosened. The arrangement of the bolts in the flange holes allows for radial tolerances, which may lead to enclosure and conductor not being sufficiently concentric. Radial tolerances may also lead to edges inside the housings, which are detrimental to the dielectric design.

[0009] EP2315326A1 , first published on 27.04.2011 in the name of ABB Technology AG, discloses a third method for connecting housings for high-voltage gas-insulated switchgear and lines by using a clamp design to connect the housing flanges. The pressure for compressing the gas sealing is achieved by using an angled slope of at least one side of the clamps, which forces the housings to move towards each other axially when tightening the clamp. This requires fewer bolts and less assembly work than for a standard flange. However, the radial space requirement around the clamp-flange connection is as large as in conventional screwed or bolted flanges. Therefore, the clamp-flange is not suitable for space-saving arrangements of three phases in electrical power transmission or distribution systems.

[0010] 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 of axial or angular adjustability. SUMMARY OF THE INVENTION

[0011] Therefore, it is an object of the present disclosure to provide an improved gastight enclosure for a gas-insulated medium-voltage or high-voltage apparatus, which addresses the disadvantages of the conventional enclosures. In particular, it is an object of the present disclosure to provide improved gas-tight enclosure for a gas-insulated medium-voltage or high-voltage apparatus, which is very compact, simple to assemble and disassemble and I or which enables limited movement between at least some parts of gas-tight enclosure for a gas-insulated medium-voltage or high-voltage apparatus. Further aspects of the invention are directed to a gas-insulated medium-voltage or high-voltage apparatus comprising such a gas-tight enclosure and to a method for producing and assembling such a gas-tight enclosure.

[0012] 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.

[0013] According to the present disclosure, a gas-tight enclosure for a gas-insulated medium-voltage or high-voltage apparatus is specified. The gas-tight enclosure comprises a first enclosure tube and a second enclosure tube, both extending along their longitudinal axis and a connection portion arranged between the first enclosure tube and the second enclosure tube for providing a gas-tight connection between a first end of the first enclosure tube and a second end of the second enclosure tube. In other words, the connection portion forms part of the first enclosure tube and the second enclosure tube and connects them with each other in the desired gas-tight manner. In order to achieve the desired advantages, the connection portion comprises a flexible spring bracket connecting the first end and the second end and enabling limited spring loaded movement between the first end and the second end. The flexible spring bracket is a mechanical part, which is arranged on the first end of the first enclosure tube and the second end of the second enclosure tube, preferably rigidly. Further, the flexible spring is, within limits, flexible, which enables that the first enclosure tube and the second enclosure tube are spring loaded moveable within predetermined limits with respect to each other. The flexible spring element enables thereby to compensate for manufacturing deviations, installation deviations, temperature compensation or enables to arrange or install the first enclosure tube and the second enclosure tube at a predefined axial distance with respect to each other and / or at a predefined angular orientation with respect to each other, which may deviate from a neutral position. The flexible spring element makes the gas-tight enclosure more flexible and useable for a variety of different applications.

[0014] The connection portion further advantageously comprises a dynamic sealing element arranged between the first end and the second end. The dynamic sealing element provides dynamic sealing between the first end and the second end in such a manner that a gas-escape path between the first end and the second end is sealed in a gas-tight manner even if the first end and the second end are moved with respect to each other. The dynamic sealing enables that the gas-tight seal between the first end and the second end is kept tight or closed even when the first enclosure tube and the second enclosure tube are moved, within the predetermined limits, with respect to each other. The term “dynamic” in this context means that movement of the first end with respect to the second end or vice versa does not affect the sealing properties of the sealing element. The gas-tight enclosure according to the present disclosure enables by its unique features that a gas-tight sealing is formed, that the first enclosure tube and the second enclosure tube are, within limits, moveable with respect to each other without affecting the sealing properties and at the same time to build in radial direction extremely slim, compared to the known standard screwed flange design.

[0015] In a preferred variation, the connection portion enables limited axial spring loaded movement between the first end and the second end along the longitudinal axis and I or enables limited angular spring loaded movement between the first end and the second end around a point of rotation. In other words, the flexible spring bracket and the entire connecting portion is configured to enable limited axial displacement between the first enclosure tube and the second enclosure tube towards each other or away from each other and I or is configured to enables limited angular movement between the first enclosure tube and the second enclosure tube, preferably in any angular direction. It is therefore possible to advantageously adjust for installation deviations, build a curved gas-tight enclosure (within predefined limits) and adjust the arrangement of the first enclosure tube with respect to the second enclosure tube on site.

[0016] The flexible spring bracket may be arranged on one predefined position around the connection portion (in circumferential direction). Further, a plurality of flexible spring brackets may be arranged on a plurality of predefined position around the connection portion, preferably arranged diametrically opposed. In a further embodiment, the flexible spring bracket may surround completely or almost completely the first end or second end. An advantageous installation is realizable when the flexible spring bracket has at least partially a ring shape configured to encompass the first end and the second end at least partially, preferably with a constant thickness. The flexible spring bracket may follow the shape of the first enclosure tube and or the second enclosure tube, in particular may have similar radial extensions, such that it is advantageously arrangeable on the respective first end and second end. The flexible spring bracket may have the constant thickness along its axial extension. The flexible spring bracket may be made of bended sheet metal.

[0017] It is preferred that the thickness of the flexible spring bracket is in a range from 0.5 mm to 2mm, more preferably in a range from 0.8 mm to 1 mm. The thickness may vary along the axial extension for providing the required spring properties.

[0018] In a further embodiment, the flexible spring bracket may be arranged on one predefined position around the connection portion (in circumferential direction). Further, a plurality of flexible spring brackets may be arranged on a plurality of predefined position around the connection portion, preferably arranged at least partially diametrically opposed. In a further embodiment, the flexible spring bracket may surround the first end or second end completely or almost completely.

[0019] It is further advantageous when the flexible spring bracket has in its resting state at its axial ends a smaller radial extension with respect to its axial center having a larger axial extension, thereby providing the spring loaded flexibility. The flexible spring bracket provides the required spring force, due to its shape, on the connected parts, if the flexible spring bracket is elastically deformed away from its resting state. The desired spring force is for example realized by the shape of the flexible spring bracket. In case the flexible spring bracket has on its axial ends a smaller radial extension compared to its axial center, the required spring properties are realized. The flexible spring bracket may thereby have along its longitudinal section view the shape of a dome, a double pitched roof, of an arch and I or any other shape enabling the limited spring loaded movement.

[0020] In a further embodiment, the flexible bracket has in its resting state at its axial ends a larger radial extension with respect to its axial center having a smaller radial extension, thereby providing the spring loaded flexibility. The flexible bracket may have an M-shape, having larger radial extensions at the axial ends compared to its axial center. The axial center may have a flat center portion, which is configured to contact the first end and I or the second end. On the flat portion, a belt or tension strap may be arranged for arranging, preferably rigidly arranging, the flexible spring bracket on the first end and the second end.

[0021] In another embodiment, the required limited spring loaded movement provided by the flexible spring bracket is (additionally) achieved via different material thickness at least along the axial extension of the flexible spring bracket. In another embodiment, the flexible spring bracket is made of elastic material or a material combination for enabling the limited spring loaded movement.

[0022] Further, the flexible spring bracket may comprise a predetermined breaking line, which determines a maximum possible force, which may act on the gas-tight enclosure. In another embodiment, the flexible spring bracket comprises a plurality of ring segments arranged in circumferential direction next to each other thereby forming the flexible spring bracket. The ring segments enable that the flexible spring bracket is advantageously bendable around the first end and the second end. Further, the ring segments enable that the flexible spring bracket is advantageously bendable due to individual movement of the ring segments, thereby advantageously compensate movement, in particular different movement, in particular angular movement, around the circumferential direction.

[0023] In its simplest form, the flexible spring bracket is made of only one ring segment or a plurality of unconnected ring segments arranged around the first end and second end, preferably at least partially diametrically opposed. Different ring segments, with different spring properties, may be arranged around the first end and second end in order to provide a directional dependent spring force and I or to provide a preload and / or a predefined angular orientation of the first enclosure tube and the second enclosure tube. The ring segments are advantageously manufactured, manageable on site and simple to engage on the first end and the second end.

[0024] In an embodiment, the ring segments are connected at least partially with respect to each other, preferably on one or on both of their axial ends and / or at their axial center thereby forming the flexible spring bracket. Connecting the ring segments at their axial end, for example via a material connection, a joint connection, a screwed connection or any other connection enables that the spring force acts on the first end and on the second end because the axial center of the different ring segments are not connected with each other and can move radially freely. The flexible spring bracket is advantageously manufacturable when it is made at least partially of a sheet metal, preferably a bended sheet metal, configured to be arranged on the first end and the second end. A sheet metal bending component is for example a sheet metal part, which is cut, e.g. via lasers or water, and afterward bended into the desired shape. The flexible spring bracket, in particular the bended portions are afterwards heat treated for stress relief.

[0025] Advantageous spring properties are realizable when the flexible spring bracket is made of spring steel. The spring steel is for example X10CrNi18-8, 38Si7, 61 SiCr7, 52CrMoV4, 51 CrV4 and / or C67E / C67S.

[0026] Further, the thickness and I or geometrical dimensions of the flexible spring bracket is / are preferably selected based on the desired spring characteristic curve for providing the desired limited spring loaded movement, preferably in axial and I or angular direction. The thickness and the geometrical dimensions, like radial extensions at different axial positions of the flexible spring bracket determine the spring characteristic curve and thereby the spring properties of the flexible spring bracket.

[0027] The spring properties are further advantageously adjustable by providing on the flexible spring bracket, in particular on the ring segments of the flexible spring bracket, openings, preferably slit like openings extending in axial direction, through which material is removed from the ring segments or the flexible spring bracket, which sets or adjusts the spring force of the flexible spring bracket. The openings may further be bores, cuts or material rejuvenations. It is further conceivable that the openings are arranged circumferentially in a varying manner around the flexible spring bracket, for example, the dimensions of the openings may vary or the number of the openings (per segment) may vary, which creates a varying spring characteristic curve in circumferential direction of the flexible spring bracket. This may be used to arrange the first enclosure tube and the second enclosure tube with a predefined angular orientation with respect to each other.

[0028] In an embodiment, the portions of the ring segments, which engage with depressions of the first end and I or second end, may have a radius, which corresponds to the radius of the depressions of the first end and I or the second end. The ring segments thereby contact the bottom of the depression advantageously.

[0029] In a further embodiment, the flexible spring bracket comprises a fastener, which is configured to connect both ends of the flexible spring bracket with each other such that the flexible spring bracket is rigidly arranged on the first end and the second end. The fastener is for example a clip, or a combination of protrusion, which is engagable into a respective depression.

[0030] The flexible spring bracket is advantageously arrangeble on the first end and the second end when the first end comprises a first depression or first groove, preferably ring shaped and extending circumferentially around the first end, and the second end comprises a second depression or second groove, preferably ring shaped end extending circumferentially around the second end. The flexible bracket may engage with the first depression and the second depression for connecting the first end with the second end. In a further embodiment, the first axial end of the flexible spring bracket engages with the first depression and the second axial end of the flexible spring bracket engages with the second depression for enabling the arrangement of the flexible spring bracket on the first end and the second end. The respective portions of the flexibles spring bracket, which are configured to engage with the depressions on the first end and the second end, are preferably manufactured such that they engage with the respective depressions without clearance. In other words, at least some of the dimensions of the respective depression correspond to at least some dimensions of the respective portions of the flexible spring bracket.

[0031] The axial movement of the first end towards the second end or vice versa is advantageously limitable when the connection portion, in particular the first end and I or the second end comprises an axial stop, which limits the axial movement of the first end towards the second end or vice versa.

[0032] The axial movement of the first end away from the second end and vice versa is advantageously limitable when the flexible spring bracket defines, by its shape a maximum possible axial displacement between the first end and the second end. The stop and the maximum possible axial displacement thereby limit axial movement of the first end and the second end in both axial directions.

[0033] The angular movement between the first end and the second end is advantageously limited when the connection portion, in particular the first end and I or the second end comprises an angular stop, which limits angular movement between the first end and the second end. The angular stop is for example a surface of the first end and I or the second end, which limits the maximum possible angular rotation / movement between the first end and the second end.

[0034] In an embodiment, the first end and the second end may comprise axially segments having different radial extensions, which are configured to overlap with respect to each other such that the gas-escape path has a segment running along a direction having a directional component parallel to the longitudinal axis, and wherein the sealing element is provided for sealing in this segment.

[0035] In a further embodiment, the different radial extensions of the first end and the second end, in particular of the overlapping segment determine the maximum angular movement between the first end and the second end. In other words, a radial clearance between the overlapping segments determines the maximum possible angular movement between the first end and the second end. Further, the presence of the clearance does not affect the gas-tight sealing because the dynamic sealing element bridges the clearance.

[0036] In an embodiment, the maximum angular movement between the first end and the second end is preferably in the range from 0° to 5°, more preferably in the range from 0.5° to 2.5°.

[0037] In an advantageous variation, the maximum possible axial movement of the first end towards the second end or vice versa starting from a resting state is 2,5 mm or lower, preferably 1 mm or lower and I or wherein the maximum possible axial movement of the first end away from the second end or vice versa starting from a resting state is 5 mm or lower, preferably 3 mm or lower. Advantageous sealing properties are realizable when the dynamic sealing element comprises two or more sealing rings, preferably arranged axially next to each other. The dynamic sealing element is according to this embodiment made of a plurality of sealing rings, arranged in the connection portion of the first enclosure tube and the second enclosure tube. Having a plurality of sealing rings provides redundancy. It is further advantageous when the dynamic sealing element or the respective sealing rings, is I are arranged in respective depressions I nuts provided in the first end or the second end. The depressions are for example arranged in axially extending surfaces of the first end or the second end. The depressions are e.g. tilted, for advantageously holding the flexible spring bracket.

[0038] A leak tightness test is advantageously feasible when the first end or the second end comprises an opening, preferably sealable, extending into an annular space limited, preferably axially limited, by two of the sealing rings and limited, preferably radially limited, by the first end and the second end, wherein the sealable opening provides access for pressure testing of the gas-tight sealing. The pressure testing may comprise to pump gas in the annular space through the opening and measure the pressure drop over time.

[0039] The desired dynamic sealing is advantageously realizable when the sealing element, in particular the sealing rings, has or have a plurality of sealing lips, preferably four sealing lips, thereby forming an X-sealing-ring.

[0040] The required power transfer or current transfer between the first enclosure tube and the second enclosure tube via the connection portion is advantageously in all possible orientations between the first enclosure tube and the second enclosure tube realizable when the connection portion comprises an electrical current transfer element, preferably in the shape of a closed spiral spring, arranged between the first end and the second end for the transfer of current during operation of the gas-tight enclosure between the first end and the second end. The spiral spring electrically connects advantageously, due to its flexibility, the first enclosure tube and the second enclosure tube with each other, even when the first end and the second end move with respect to each other.

[0041] The electrical current transfer element is preferably arranged in an in circumferential direction arranged depression in the first end or second end. The thickness of the electrical current transfer element in an uncompressed state is preferably larger compared to the depth of the depression, thereby ensuring the required electrical contact. The same applies preferably to the sealing element.

[0042] It is further advantageous when the electrical current transfer element is arranged axially between two sealing rings, which advantageously reduces contact corrosion. The electrical current transfer element is preferably made of spring bronze (CuZr).

[0043] In an embodiment, the gas-escape path, when seen in a longitudinal section of the gas-tight enclosure, has a meandering shape having at least two opposite bends, in particular an S-shape, or a U-shape or a C-shape. The two opposite bends improve the gas tightness. Each of the segments / bends may comprise one or more sealing rings for providing the gas tight sealing. In a further embodiment, the sealing rings may be made of different material, which depends on their point of use. The sealing ring arranged next to the outside area may be of a different material compared to the sealing ring arranged next to the inside, with respect to the sealing path.

[0044] The gas-tight enclosure is further advantageously realizable when the connection portion provides a radially acting compression force onto the sealing element for sealing the gas-escape path and I or wherein the connection portion provides a radially acting compression force onto the electrical current transfer element for securing the transfer of current during operation of the gas-tight enclosure. The connection portion, in particular the flexible spring bracket, according to this embodiment provide a radially acting compression force, by pressing the first end and the second end towards each other, which improves the gas tight sealing and improves the electrical connection for current transfer.

[0045] In a further embodiment, the first end and I or the second end comprise(s) a chamfer or a rounding on the edge, which is slid above the dynamic sealing element. The chamfer or rounding enables an advantageous sliding of the first end onto the second end during assembling. The chamfer / rounding, the respective surfaces or the sealing rings may further be lubricated or greased for an advantageous assembling.

[0046] In an embodiment, the flexible spring bracket determines by its shape the geometrical resting state arrangement, preferably the axial and angular arrangement, between the first enclosure tube and the second enclosure tube, in which the flexible spring bracket does not apply a spring force onto the first enclosure tube and the second enclosure tube. For example, in the resting state of the flexible spring bracket, the first enclosure tube and the second enclosure tube may be arranged coaxially with respect to each other and may be arranged at a predefined axial distance with respect to each other, such that the axial stops do not engage with each other. In another example, the resting state of the flexible spring bracket may further determine that the first enclosure tube and the second enclosure tube are arranged at a predefined angular orientation, deviating from the coaxial arrangement, with respect to each other. In other words, the orientation and arrangement between the first enclosure tube and the second enclosure tube may be determined by the flexible spring bracket, and in particular by its shape.

[0047] In a further embodiment, the connecting portion is at least partially covered by a cap / cover, which surrounds at least partially the connecting portion, thereby protecting the connecting portion, in particular from contamination of dust or particles, which may enter the connecting portion and affect the movement or the sealing. The cap / cover may be a flexible injection molded plastic part.

[0048] According to a further aspect of the present disclosure, a gas-insulated mediumvoltage of high-voltage apparatus comprising a gas-tight enclosure as described above and I or hereinafter is specified.

[0049] 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). 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, technical air (e.g. 80% N2 und 20% O2), O2, N2, CO2, SFe, alternative synthetic insulation gases, and mixtures thereof.

[0050] In an embodiment, the gas-insulated medium-voltage of high-voltage apparatus may further comprise additional one fixed connection portion, e.g. arranged to a flexible connection portion, which connects via non-flexible bracket one enclosure tube with another enclosure tube.

[0051] In a yet further aspect, a method of producing and assembling a gas-tight enclosure, in particular a gas-tight enclosure as specified above and I or hereinafter, for a gas-insulated medium-voltage or high-voltage apparatus is specified. The method comprising the following steps.

[0052] Producing, in particular machining, into a first end of a first enclosure tube a first connection face. The first end is for example milled and I or turned onto the first enclosure tube, comprising the required axially extending faces, radially extending faces and I or depressions, protrusions and I or openings.

[0053] Producing, in particular machining, into a second end of a second enclosure tube a mating second connection face. The second end is for example milled and I or turned onto the second enclosure tube, comprising the required axially extending faces, radially extending faces and I or depressions, protrusions and I or openings. Providing on the machined first end or second end preferably at the first connection face or the second connection face, a dynamic sealing element, preferably a plurality of sealing rings forming the dynamic sealing element. The dynamic sealing element is preferably arranged in the respective machined depressions.

[0054] Thrusting the first and mating second connection faces onto one another thereby providing a gas-tight connection portion between the first and second enclosure tube.

[0055] Arranging a flexible spring bracket having a diameter and axial width adapted to the first and second enclosure tube on the first end and the second end for connecting the first end and the second end and enabling limited spring loaded movement between the first end and the second end.

[0056] The method steps as described above are at least partially also advantageously executable on an installation site of the gas-insulated medium-voltage or high- voltage apparatus. Further, the flexible spring bracket enables to produce a curved gas-insulated medium-voltage or high-voltage apparatus, to adjust for length variation, for example due to temperature differences or due to geometrical deviations.

[0057] In an embodiment, the method further comprises the steps of:

[0058] Producing, in particular machining, depressions or grooves in the first and second enclosure tube. Producing, in particular machining, the flexible spring bracket with inward protrusions that mate with the depressions in the first and second enclosure.

[0059] Arranging the flexible spring bracket in the depressions in the first and second enclosure tube for connecting the first end and the second end, thereby enabling limited spring loaded movement between the first end and the second end.

[0060] In a further embodiment, the first enclosure tube and the second enclosure tube are machined to have the same inner and outer diameter, respectively.

[0061] 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.

[0062] BRIEF DESCRIPTION OF THE FIGURES

[0063] The herein described invention 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 invention described in the appended claims. The drawings are showing in: Fig. 1 a front view of a single-phase gas-insulated line (GIL) according to a first embodiment;

[0064] Fig. 2 a longitudinal section view of the single-phase gas-insulated line (GIL) of Figure 1 according to a first embodiment; Fig. 3 a detailed view of the longitudinal section view of the single-phase gas- insulated line (GIL) of Figure 2 according to a first embodiment;

[0065] Fig. 4 a detailed view of a connection portion of the single-phase gas-insulated line (GIL) of Figure 3 according to a first embodiment;

[0066] Fig. 5 a detailed view of the conductor portion of single-phase gas-insulated line (GIL) of Figure 3 according to a first embodiment;

[0067] Fig. 6 a front view of a single-phase gas-insulated line (GIL) according to a second embodiment;

[0068] Fig. 7 a longitudinal section view of the single-phase gas-insulated line (GIL) of Figure 6 according to a second embodiment; Fig. 8 a detailed view of the longitudinal section view of the single-phase gas- insulated line (GIL) of Figure 7 according to a second embodiment;

[0069] Fig. 9 a detailed view of a connection portion of the single-phase gas-insulated line (GIL) of Figure 8 according to a second embodiment; Fig. 10 a detailed view of the conductor portion of single-phase gas-insulated line (GIL) of Figure 8 according to a second embodiment;

[0070] Fig. 11 a perspective view of a flexible spring bracket in a neutral position according to a first embodiment; Fig. 12 a perspective view of the flexible spring bracket of Figure 11 in a maximum axial displacement position;

[0071] Fig. 13 two longitudinal section views of the connection portion according to a third embodiment in a neutral position and in a maximum axial displacement position; Fig. 14 a perspective view of the flexible spring bracket according to a second embodiment;

[0072] Fig. 15 a perspective view of the flexible spring bracket according to a third embodiment;

[0073] Fig. 16 two longitudinal section views of the connection portion according to a fourth embodiment in a neutral position and in a maximum axial displacement position;

[0074] Fig. 17 two longitudinal section views of the connection portion according to a fifth embodiment in an angular displacement position; Fig. 18 two longitudinal section views of the connection portion according to the fifth embodiment in an angular and axial displacement position;

[0075] Fig. 19 two longitudinal section views of the connection portion according to a sixth embodiment in an angular displacement position;

[0076] Fig. 20 two longitudinal section views of the connection portion according to the sixth embodiment in an angular and axial displacement position.

[0077] DETAILED DESCRIPTION OF THE FIGURES

[0078] 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.

[0079] Figure 1 shows a front view of a single-phase gas-insulated line (GIL) according to a first embodiment. The single-phase gas-insulated line comprises a gas-tight enclosure 1 . The gas-tight enclosure 1 comprises a plurality of segments, which are interconnectable, thereby forming the single-phase gas-insulated line. Figure 1 in particular shows three segments and refers to a first enclosure tube 2 and a second enclosure tube 3, which are connected to each other. The first enclosure tube 2 and the second enclosure tube 3 and further enclosure tubes are connected to each other via a connecting portion 4. The connection portion 4 is surrounded and shielded from the outside via a cap 15, surrounding the connection portion 4. The first enclosure tube 2 comprise a respective outside face 2a and the second enclosure tube 3 comprises a respective outside face 3a. The enclosure tubes 2, 3 according to Figure 1 have the shape of ring cylinders, other shapes like rectangular cylinders, are of course also conceivable. Figure 1 further shows a conductor 12, which is arranged inside the respective enclosure tube and which is configured for power transfer. Figure 1 further indicates a longitudinal section view AH.

[0080] Figure 2 shows a longitudinal section view of the single-phase gas-insulated line (GIL) of Figure 1 along the indicated section view AH. Figure 2 advantageously shows the interior of the gas-tight enclosure 1 . The gas-tight enclosure 1 further comprises the centrally arranged conductor 12, which is configured for power transfer from one segment to the next segment. The conductors 12 are further connected to the high / medium voltage source. The conductor 12 is surrounded by an insulation gas compartment 13, which is radially limited by the respective enclosure tubes 2, 3. The inside volume of the gas compartment 13 or busducts are filled with an insulation gas, such as air, CO2, N2, SFe or insulation gas mixtures at elevated pressure. Typical insulation gas pressures are in a range from 3 bar to10 bar.

[0081] The conductor 12 is further kept in position and connected with the enclosure tubes 2, 3 via spacers 8, which are preferably disk shaped and which preferably comprise openings for enabling gas transfer between different gas compartments

[0082] 13. The spaces 8 are preferably made of an insulating material.

[0083] In embodiments, the disclosed integrated flange design may be used to connect also gas-insulated switchgear components other than a gas-insulated line, such as: circuit breakers, disconnectors, busbars, earthing switches, compensator elements, angle connections, end covers, etc..

[0084] Figure 2 further advantageously shows the connection portion 4 connecting a first end 20 of the first enclosure tube 2 with a first end 30 of the second enclosure tube 30. It is further visible that the different connectors 12 are connected with each other via conductor connectors 12a. Figure 2 further indicated the detailed view Al.

[0085] Figure 3 shows a detailed view of the longitudinal section view of the singlephase gas-insulated line (GIL) of Figure 2 as indicated by the auxiliary lines Al. The detailed view of Figure 3 shows the entire connection portion 4 from the radial outer portions until the radial center portion. When starting from the center, the connection portion 4 and the gas-tight enclosure 1 extends along the longitudinal axis z in axial direction. The part arranged in the radial center is the conductor connector 12a, which connects two conductors 12 with each other for power transfer. The connection is at least partially enabled via connector electrical current transfer elements 7. Two connector electrical current transfer elements 7 are arranged on both axial ends of the conductor connector 12a. Both are arranged in respective grooves or nuts in the conductor connector 12a. The connector elec- trical current transfer elements 7 are preferably spiral springs, which contact during operation and in an assembled state the respective conductor 12 and the conductor connector 12a. The figures advantageously show that the conductor 12 has a tube shape with a larger radius compared to the radius of the conductor connector 12a and is overlapping with the conductor connector 12a. It is further visible in Figure 3 that the conductors 12 are movable, in particular axially, with respect to each other. A limited axial movement does not affect the required contact between the different parts. Figure 3 further advantageously shows the connection between the spacer 8 and the conductor connector 12a. The spacer 8 is arranged axially in the center of the conductor connector 12a and extends radially outwards. Figure 3 further shows a conductor connecting element 81 , which connects the spacer 8, the conductors 12 and the conductor connector 12a with each other as desired.

[0086] Figure 3 further shows that the spacer 8 extends radially until it reaches the first enclosure tube 2 and / or the second enclosure tube 3, thereby holding the conductor parts 12, 12a etc. in position. The first enclosure tube 2 comprises a first end 20 having a specific shape and the second enclosure tube 3 comprises a second end 30 having a specific shape mating with the first end 20. It is visible that both ends 20, 30 are shaped compatible with each other such that they overlap partially. More details regarding the first end 20 and the second end are explained below with reference to figure 4. Figure 3 further shows a flexible spring bracket 9 as part of the connection portion 4, which is arranged radially outside of the first end 20 and the second end 30 and configured to enable limited spring loaded movement between the first end 20 and the second end 30. The flexible spring bracket 9 is covered by the cap 15, which surrounds the flexible spring bracket 9 from the outside. Figure 3 further indicates the presence of a sealing element 5 arranged between the first end 20 and the second end 30 and configured to provide dynamic sealing in such a manner that a gas-escape path L between the first end 20 and the second end 30 is sealed in a gas-tight manner.

[0087] The figures 1 to 3 show advantageously that many parts, e.g. the conductor 12, the conductor connector 12a, the spacer 8, the first enclosure tube 2, the second enclosure tube 3 and I or the flexible spring bracket 9 are shaped rotationally symmetric.

[0088] The embodiment of the gas-tight enclosure 1 shown in the Figures 1 , 2 and 3 shows the gas-tight enclosure 1 in its neutral position or in its resting position 100a.

[0089] Figure 3 further indicates via auxiliary lines T and V further detailed views, which will be explained below with respect to figures 4 and 5.

[0090] Figure 4 shows a detailed view of the connection portion 4 of the single-phase gas-insulated line (GIL) of Figure 3 (T). Figure 4 shows a detail of the connection portion 4, in particular the connection between the first enclosure tube 2 and the second enclosure tube 3. Figure 4 advantageously shows the different surfaces of the first end 20 and the second end 30 of the respective enclosure tubes 2, 3, which engage I overlap with each other. The radial outermost extension of the first enclosure tube 2 corresponds to the radial outermost extension of the second enclosure tube 3 and I or the radial innermost extension of the first enclosure tube 2 corresponds to the radial innermost extension of the second enclosure tube 3. In other words, the first enclosure tube 2 and the second enclosure tube 3 have the same thickness. The respective ends 20, 30 vary in order to enable the required functionalities. It is further visible that on an outside face of the first enclosure tube 2a a first depression 2b or groove is formed, in which a first protrusion 90 of the flexible spring bracket 9 is arranged. On the outside face of the second enclosure tube 3a a second depression 3b or groove is formed, in which a second protrusion 91 of the flexible spring bracket 9 is arranged. It is further visible that the axial ends of the cap 15 are also arranged on respective depressions I grooves in the first enclosure tube 2 and the second enclosure tube 3. The cap 15 is for example made of a flexible plastic material, protecting the connection portion 4.

[0091] Figure 4 further advantageously shows the dynamic sealing 5, which is arranged between two axially extending and overlapping contacting surfaces of the first end 20 and the second end 30. The dynamic sealing 5 according to this embodiment comprises two sealing rings 5a, 5b, which are arranged axially next to each other in respective sealing grooves 50, which are arranged in the second face 30. The sealing rings 5 are X-sealing rings having four sealing lips, two of which contact the first end 20 and two of which contact the second end 30. Figure 4 further shows that the first end 20 and the second end 30 form axial stops 102, which are configured to limit the axial movement of the first enclosure tube 2 towards the second enclosure tube 3 or vice versa. It is further visible that the connection portion 4 forms a spacer groove 80 for arranging the spacer 8. The spacer groove 80 extends from the inner surface of the first enclosure tube 2 until a groove bottom formed preferably by the same axially extending surface, which is also in contact with the sealing element 5. The spacer groove 80 is preferably axially limited in one direction by the second end 30, as visible in Figure 4. The spacer 8 can thereby advantageously be connected to the first and the second enclosure tube 2, 3. Figure 4 further shows that the electrical current transfer element 6, having the shape of a spiral spring, is arranged between the first sealing ring 5a and the second sealing ring 5b. The electrical current transfer element 6 is arranged in a respective electrical current transfer element groove 60 provided in the second end 30.

[0092] Figure 4 further shows the flexible spring bracket 9 in detail. The flexible spring bracket 9 has the shape of a double pitched roof, which provides the required spring flexibility, other shapes are of course also conceivable. The flexible spring bracket 9 has on its axial ends protrusions 90, 91 extending radially inwardly, which are configured to engage with the respective depressions 2b, 3b in the first end 20 and the second end 30. The dimensions of the protrusions 90, 91 preferably correspond to the dimensions of the depressions 2b, 3b.

[0093] Figure 4 advantageously shows that axial displacement between the first end 20 and the second end 30 is, within limits, possible. The limits are determined by the stops 102 and the flexible spring bracket 9. The sealing element 5, in particular the sealing rings 5a, 5b slide, when the first end 20 is axially moved, along the respective sealing surface of the first end 20, without leakage.

[0094] Figure 4 further shows that the spacer groove 80 can be provided with rounded edges produced or machined into the first and second enclosure tubes 2, 3 with specified radii for dielectric stress relief at triple points between the enclosure 1 , the insulation gas compartment 13 and the insulating spacer 8, as well as in the insulating spacer 8 of the gas-insulated medium-voltage or high-voltage apparatus. It is further visible that the spacer 8 itself is provided with a specific rounded edges for dielectric stress relief.

[0095] Figure 5 shows a detailed view of the connection portion 4 showing the connection between a first conductor 12 from the first enclosure tube 1 and a second conductor 12 from a second enclosure tube 2. Figure 5 advantageously show the conductor connector 12a and the arrangement of the spacer 8 between the conductors 12. Figure 5 further shows the conductor connecting elements 81 , which partially surround the conductors 12 and which are rigidly arranged, preferably via press fit, on the conductor connector 12a. The conductor connecting elements 81 further preferably provide a stop, which limits the axial movement of the conductors 12 towards each other. Figure 5 further shows advantageously the four conductor electrical current transfer elements 7, which have the shape of a spiral spring. The conductor electrical current transfer elements 7 are arranged in respective grooves I depressions of the conductor connector 12a and extend circumferentially around the conductor connector 12a. The conductor electrical current transfer element 7 enable the electrical contact between the different parts, even when moved or when arranged at different positions I orientation, within the respective limits, determined e.g. at least partially by the axial gap 101. It is visible in Figure 5 that the radius of the conductor connector 12a at the overlapping portion is smaller than the radius of the conductor 12 at the overlapping portion, which enables limited angular movement, without losing electrical contact (due to the respective conductor electrical current transfer element 7). The Figures 1 to 5 show the gas tight enclosure 1 in the resting state or neutral state Oa of the flexible spring bracket 9. In other words, the flexible spring bracket 9 as shown in the figures 1 to 5 does not apply any spring force due to a displacement from the first end 20 or the second end 30 away from the resting state 100a.

[0096] The Figures 6 to 10 correspond to the Figures 1 to 5 and show the single-phase gas-insulated line in its different views and detailed views. The Figures 6 to 10 differ from the Figures 1 to 5 in that the first enclosure tube 2 and the second enclosure tube 3 are arranged at the maximum axial displacement position 100b. The maximum axial displacement position 100b determines the position in which the first end 20 and the second end 30 are arranged at the maximum possible axial distance away from each other determined by the flexible spring bracket 9. Figure 8, 9 and 10 show this most advantageously. In these Figures, the flexible spring bracket 9 is at its maximum axial extension and does not have a double pitched roof shape. Instead the flexible spring bracket 9 has a flat shape, thereby applied the maximum spring force on the first end 20 and the second end 30. The figures 9 and 10 advantageously show that the axial gap 101 between the first end 20 and the second end 30 is larger compared to the axial gap 101 shown in the figures 4 and 5.

[0097] The Figures 6 to 10 further show that the sealing 5, in particular the sealing rings 5a, 5b still engage and seal gas tight the gas escape path L even at the maximum axial extension / displacement position 100b. The figures, in particular figure 9 advantageously show that the spacer 8 remains in contact with the first end 20. The spacer 8 may be arranged rigidly in contact with the first end 20, e.g. via press fit.

[0098] Figure 11 shows a perspective view of the flexible spring bracket 9 in a neutral position 100a according to the embodiment as shown in the figures 1 to 10. The flexible spring bracket 9 has in the neutral position 100a the double pitched roof shape as advantageously visible in figure 11 . Figure 11 further shows that the flexible spring bracket 9 is connected with the first enclosure tube 2 and the second enclosure tube 3.

[0099] Figure 12 shows a perspective view of the flexible spring bracket 9 of Figure 11 in a maximum axial displacement position 100b. In this position, the flexible spring bracket 9 has a flat shape and applies the maximum possible spring force on the first enclosure tube 2 and the second enclosure tube 3.

[0100] Figure 13 shows two longitudinal section views of the connection portion 4 according to a third embodiment. The first shown longitudinal section view shows the connection portion 4 in a neutral position 100a and the second shown longitudinal section view shows the connection portion 4 in a maximum axial displacement position 100b. Figure 13 further shows black arrows, which indicate the displacement direction. In addition, figure 13 comprises auxiliary lines 201 , 202, 203 and 204, which connect the first longitudinal section view with the second longitudinal section view for indicating the axial displacement. Figure 13 advantageously shows an axial delta 200, which represents the maximum axial displacement possible by elastic deformation of the flexible spring element 9. The embodiment of figure 13 further differs from the embodiment shown in the figures 1 to 10 in several ways. The arrangement of the different parts and the shape of the first end 20 and the second end 30 differ substantially. In detail: The overlapping portion is switched. The second end 30 overlaps the first end 20. Further, the spacer 8 is arranged in axial contact with the second end 30. The electrical current transfer element 6 is arranged axially on one side of both sealing rings 5a, 5b and not in between. The sealing rings 5a and 5b do have an O shape (compressed) forming an O-ring.

[0101] The Figure 13 further advantageously shows the gas escape path L comprising three segments. The first segment L1 extends radially and is arranged between the spacer 8 and the first end 20. The second segment L2 extend axially along the first end 20 and the second end 30 in the overlapping region. The third end L3 extends radially along the first end 20 and the second end 30. The gas escape path L shown with respect to the figures 1 to 10 also has three segments.

[0102] The Figure 13 further shows a sealable opening 16 extending into an annular space axially limited by the two sealing rings 5a, 5b and radially limited by the first end 20 and the second end 30. The sealable opening 16 provides access for pressure testing of the gas-tight sealing.

[0103] Figure 14 shows a perspective view of the flexible spring bracket 9 according to a second embodiment. In this embodiment comprises a plurality of ring segments 92, which are laterally arranged next to each other and form in combination the flexible spring bracket 9. The ring segments 92 are separated with each other via axial slits / openings. According to this embodiment, the ring segments 92 are connected with each other via a material connection on the axial ends of the flexible spring bracket 9. The axial slits 93 advantageously enable to provide the limited spring loaded movement. The flexible spring bracket 9 as shown in Figure 14 forms a closed ring. The closure is for example realized by welding the ends together.

[0104] Figure 15 shows a perspective view of the flexible spring bracket 9 according to a third embodiment. In this embodiment, the flexible spring bracket 9 also comprises ring segments 92, which are separated via axial slits 93. The flexible spring bracket 9 according to this embodiment differs from the flexible spring bracket from the embodiment shown with respect to figure 14 in the connection of the different ring segments 92. The ring segments 92 according to this embodiment are connected at or near the axial center with each other. The axial ends of the ring segments are free and not connected with each other. Figure 15 further shows a different circumferential connection. The flexible spring bracket 9 according to this embodiment is circumferentially connected via a bracket clip 94 or fastener, having two extensions engaging in corresponding openings or slits. The flexible spring bracket 9 is for example arranged around the first enclosure tube 2 and the second enclosure tube 3 and fixed by the bracket clip 94. Other connections are of course also conceivable.

[0105] The flexible spring bracket 9 according to the embodiments shown in the figures 14 and 15 is e.g. manufactured out of sheet metal, which is cut for forming the axial stilts 93, thereby forming also the ring segments 92 and which is afterwards bend for forming the first and the second protrusion 90, 91 and the general shape of the flexible spring bracket 9. Bending further makes out of a sheet metal the required spring.

[0106] The flexible spring bracket 9 according to the embodiments shown in the figures 14 and 15 may further comprise additional axial slits or openings, preferably extending axially. These additional axial slits may be used to adjust the spring force. The ring segments 92 and / or the additional axial slits may further vary in circumferential direction.

[0107] Figure 16 further two longitudinal section views of the connection portion 4 according to a fourth embodiment in a neutral position 100a and in a maximum axial displacement position 100b. Figure 16 corresponds to figure 13 and differs only in the arranged flexible spring element 9. The flexible spring element 9 of Figure 16 is made of a plurality of ring segments 92, which are separated from each other via the axial slits 93. The detailed explanations made with respect to figure 13 applies mutatis mutandis to figure 16.

[0108] Figure 17 shows two longitudinal section views of the connection portion 4 according to a fifth embodiment in an angular displacement position 100c. The upper section view shows the upper radial end of the section view of the gas-tight enclosure 1 and the lower section view shows the lower radial end of the section view of the gas-tight enclosure 1 . In this position the first enclosure tube 2 and the second enclosure tube 3 are arranged at an angular orientation with respect to each other, which deviates from the coaxial orientation shown with respect to the figures 1 to 16. The angular deviation is for example 1 °. This is also visible in figure 17; the first enclosure tube 2 is e.g. rotated by 1 ° with respect to the second enclosure tube 2. The pivot point r is shown in figure 17. The overlapping region of the first end 20 and the second end 30 are configured to enable the 1 ° rotation, e.g. by respective radii, which provide a radial gap I clearance between the first end 20 and the second end 30 at the overlapping region enabling the angular rotation. The sealing element 5, in particular the sealing rings 5a, 5b (as shown e.g. in the previous figures) still provide the gas-tight sealing even when rotated. The white arrows in figure 17 show potential contact points and I or points of extended distance. The flexible spring bracket 9 as shown in figure 17 does not follow the angular rotation. In reality, the flexible spring bracket 9 would be capable of following the rotation. In other words, the shown conflicts in figure 17 do not correspond to reality. The flexible spring bracket 9 is designed to enable limited spring-loaded angular movement between the first enclosure tube 2 and he second enclosure tube 3 and would follow the angular movement.

[0109] Figure 18 shows two longitudinal section views of the connection portion 4 according to the fifth embodiment in an angular and axial displacement position 100b, 100c. Figure 18 differs from figure 17 in that the first enclosure tube 2 is not only angularly displaced from the neutral position, but also axially displaced. In other words, the first enclosure tube 2 and I or the second enclosure tube 3 is / are arranged axially displaced from the neutral position, causing the flexible spring element 9 to be flat, and in addition the first enclosure tube 2 is also arranged in an angular position which deviates from the coaxial angular position. Also here, the flexible spring element 9 is capable to follow the movement / orien- tation of the first enclosure tube 2 and the second enclosure tube 3. The shown geometrical conflicts do not correspond to the reality. Figure 19 shows two longitudinal section views of the connection portion 4 according to a sixth embodiment in an angular displacement position 100c.

[0110] Figure 20 shows two longitudinal section views of the connection portion according to the sixth embodiment in an angular and axial displacement position 100b, 100c.

[0111] The figures 19 and 20 correspond to the figures 17 and 18 and differ only in the flexible spring element 9. The flexible spring element 9 according to the embodiments shown with respect to the figures 19 and 20 comprises the ring segments 92 as described in more details with respect to the figures 14 and 15. The expla- nations made with respect to the embodiments shown in the figures 17 and 18 apply mutatis mutandis to the embodiment shown in the figures 19 and 20.

[0112] The enclosure, gas-insulated medium-voltage or high-voltage apparatus, and the method for producing and assembling the enclosure or apparatus can be used for installations in radially confined spaces, e.g. pipes, water pipes, tunnels etc., and / or as alternative or for avoidance or replacement of electrical medium-volt- age or high-voltage cables.

[0113] LIST OF REFERENCE SIGNS

[0114] 1 gas-tight enclosure, metal en7 conductor electrical current closure transfer element

[0115] 2 first enclosure tube 8 spacer, post-type insulator,

[0116] 2a outside face of first enclosure disk-shaped insulator, sup- tube 30 porting insulator, compartment insulator

[0117] 2b first depression in 2a, rectangular groove 80 spacer groove

[0118] 20 first end of first enclosure tube 81 conductor connecting element

[0119] 3 second enclosure tube 9 flexible spring bracket

[0120] 3a outside face of second enclo35 90 first protrusion of bracket sure tube 91 second protrusion of bracket

[0121] 3b second depression in 3a, rec92 ring segments tangular groove 93 axial slit in bracket

[0122] 30 first end of second enclosure 94 bracket clip I fastener tube

[0123] 40 12 conductor

[0124] 4 connection portion

[0125] 12a conductor connector

[0126] 5 sealing element, sealing ring

[0127] 13 insulation gas compartment

[0128] 5a first sealing ring, X-ring

[0129] 15 cap

[0130] 5b second sealing ring, X-ring

[0131] 16 pressure test opening

[0132] 50 sealing groove

[0133] 45 100a neutral position I resting posi¬

[0134] 6 electrical current transfer eletion ment

[0135] 100b maximum axial displacement

[0136] 60 electrical current transfer eleposition ment groove

[0137] 100c angular displacement position 101 axial gap L gas-escape path

[0138] 102 axial stop L1 first segment

[0139] 200 delta 10 L2 second segment

[0140] 201 first auxiliary line L3 third segment 202 second auxiliary line z longitudinal axis

[0141] 203 third auxiliary line r pivot point / point of rotation

[0142] 204 fourth auxiliary line

Claims

PATENT CLAIMS1 . Gas-tight enclosure (1 ) for a gas-insulated medium-voltage or high-voltage apparatus comprising a. a first enclosure tube (2) and a second enclosure tube (3), both extending along a longitudinal axis (z), b. a connection portion (4) arranged between the first enclosure tube (2) and the second enclosure tube (3) for providing a gas-tight connection between a first end (20) of the first enclosure tube (2) and a second end (30) of the second enclosure tube (3), the connection portion (4) comprising: i. a flexible spring bracket (9) connecting the first end (20) and the second end (30) and enabling limited spring loaded movement between the first end (20) and the second end (30), ii. a dynamic sealing element (5) arranged between the first end (20) and the second end (30), wherein the dynamic sealing element (5) provides dynamic sealing between the first end (20) and the second end (30) in such a manner that a gas-escape path (L) between the first end (20) and the second end (30) is sealed in gas-tight manner.

2. The gas-tight enclosure (1 ) according to claim 1 , wherein the connection portion (4) enables limited axial spring loaded movement between the first end (20) and the second end (30) along the longitudinal axis (z) and I or enables limited angular spring loaded movement between the first end (20) and the second end (30) around a point of rotation (r).

3. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein, the flexible spring bracket (9) has at least partially a ring shape encompassing the first end (20) and the second end (30), preferably with a constant thickness, and wherein the flexible bracket (9) has in its resting state at its axial ends a smaller radial extension with respect to its axial center having a larger radial extension, thereby providing the spring loaded flexibility or wherein the flexible bracket (9) has in its resting state at its axial ends a larger radial extension with respect to its axial center having a smaller radial extension, thereby providing the spring loaded flexibility.

4. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein the flexible spring bracket (9) has along its longitudinal section view the shape of a dome, a double pitched roof, of an arch of an M and I or any other shape providing the spring loaded flexibility enabling the limited spring loaded movement.

5. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein the flexible spring bracket (9) comprises a plurality of ring segments (92) arranged in circumferential direction next to each other thereby forming the flexible spring bracket (9), wherein the ring segments (92) are connectedonly partially with each other, preferably at one or both of their axial ends and / or at their axial center.

6. The gas-tight enclosure (1 ) according to claim 5, wherein the ring segments (92) comprise spring force setting openings, preferably extending in axial direction, through which material is removed from the ring segments (92), which preferably adjusts the spring force of the flexible spring bracket (9).

7. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein the first end (20) comprises a first depression (2b), preferably ring shaped, and the second end (30) comprises a second depression (3b), preferably ring shaped, wherein a first axial end of the flexible spring bracket (9) engages with the first depression (2b) and the second axial end of the flexible spring bracket (9) engages with the second depression (3b) for enabling the arrangement of the flexible spring bracket (9) on the first end (20) and the second end (30).

8. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein the connection portion (4), in particular the first end (20) and I or the second end (30), comprises an axial stop (102), which limits axial movement of the first end (20) towards the second end (30) or vice versa, and I or wherein the flexible spring bracket (9) defines, by its shape a maximum possible axial displacement position (100b) between the first end (20) and the second end (30), wherein the first end (20) and the second end (30) are axially moveable between the stop (102) and the maximum possible axial displacement position (100b).

9. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein the connection portion (4), in particular the first end (20) and I or the second end (30), comprises an angular stop, which limits angular movement between the first end (20) and the second end (30).

10. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein the first end (20) and the second end (30) comprise axially extending segments having different radial extensions, which are configured to overlap with respect to each other such that the gas-escape path (L) has a segment (L2) running along a direction having a directional component parallel to the longitudinal axis (z), and wherein the sealing element (5) is provided for sealing in this segment (L2).11 . The gas-tight enclosure (1 ) according to claim 10, wherein the different radial extensions of the first end (20) and the second end (30) determine the maximum angular movement between the first end (20) and the second end (30).

12. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein the maximum angular movement is preferably in the range from 0° to 5°, more preferably in the range from 0.5° to 2.5°.

13. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein the maximum possible axial displacement of the first end (20) towards the second end (30) or vice versa starting from a resting state is 2,5mm or lower, preferably 1 mm or lower, and I or wherein the maximum possible axial movement of the first end (20) away from the second end (30) or vice versa starting from a resting state is 5 mm or lower, preferably 3 mm or lower.

14. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein the dynamic sealing element (5) comprises two or more sealing rings (5a, 5b), each being arranged in a respective sealing depression (50) of the first end (20) or the second end (30), forming in combination the dynamic sealing (5).

15. The gas-tight enclosure (1 ) according to claim 14, wherein the first end (20) or the second end (30) comprises a sealable opening (16) extending into an annular space axially limited by two of the sealing rings (5a, 5b) and radially limited by the first end (20) and the second end (30), wherein the sealable opening (16) provides access for pressure testing of the gas-tight sealing.

16. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein the sealing element (5), in particular the sealing rings (5a, 5b), has or have four sealing lips, thereby forming an X-sealing-ring.

17. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein the connection portion (4) comprises an electrical current transfer element (6), preferably in the shape of a closed spiral spring, arranged between the first end (20) and the second end (30) for the transfer of current during operation of the gas-tight enclosure (1 ).

18. The gas tight enclosure (1 ) according to claim 17, wherein the electrical current transfer element (6) is arranged axially between two sealing rings (5a, 5b).

19. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein the gas-escape path (L), when seen in a longitudinal section of the gas-tight enclosure (1 ), has a meandering shape having at least two opposite bends, in particular an S-shape, or a U-shape or a C-shape.

20. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein, the connection portion (4) provides a radially acting compression force onto the sealing element (5) for sealing the gas-escape path (L) and I or wherein the connection portion (4) provides a radially acting compression force onto the electrical current transfer element (6) for securing the transfer of current during operation of the gas-tight enclosure (1 ).

21. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein the first end (20) and I or the second end (30) comprises a chamfer or a rounding on the edge, which is slid above the dynamic sealing element (5).

22. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein the flexible spring bracket (9) determines by its shape the geometrical resting state arrangement (100a), preferably the axial and angular resting state arrangement, between the first enclosure tube (2) and the second enclosure tube (3), in which the flexible spring bracket (9) does not apply aspring force onto the first enclosure tube (2) and the second enclosure tube (3).

23. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein the flexible spring bracket (9) is a sheet metal bending component.

24. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein the flexible spring bracket (9) is made of spring steel, and the thickness of the flexible spring bracket (9) is selected based on the desired spring characteristic curve for providing the desired limited spring loaded movement.

25. The gas-tight enclosure (1 ) according to any one of the preceding claims, wherein the connecting portion (4) is at least partially covered by a cap (15), which surrounds at least partially the connecting portion (4), thereby protecting the connecting portion (4).

26. Gas-insulated medium-voltage or high-voltage apparatus comprising a gastight enclosure (1 ) according to any one of the preceding claims.

27. The gas-insulated medium-voltage or high-voltage apparatus according to claim 24, 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).

28. The gas-insulated medium-voltage or high-voltage apparatus according to one of the claims 24 to 25 comprising or consisting of gas-insulated components using a pressurized insulation gas selected from the group consisting of: air, technical air, O2, N2, CO2, SFe, alternative synthetic insulation gases, and mixtures thereof.

29. Method of producing and assembling a gas-tight enclosure (1 ), in particular a gas-tight enclosure (1 ) according to any one of the preceding claims 1 to 23, for a gas-insulated medium-voltage or high-voltage apparatus, comprising the method steps of: a. producing, in particular machining, into a first end (20) of a first enclosure tube (2) a first connection face (21 ), b. producing, in particular machining, into a second end (30) of a second enclosure tube (3) a mating second connection face (31 ), c. providing on the machined first end (20) or second end (30) preferably at the first connection face (21 ) or the second connection face (31 ), a dynamic sealing element (5), d. thrusting the first and mating second connection faces (21 , 31 ) into one another thereby providing a gas-tight connection portion (4) between the first and second enclosure tube (2, 3), and e. arranging a flexible spring bracket (9) having a diameter and axial width adapted to the first and second enclosure tube (2, 3) on thefirst end (20) and the second end (30) for connecting the first end (20) and the second end (30) and enabling limited spring loaded movement between the first end (20) and the second end (30).

30. The method according to claim 27, further comprising the steps of: a. producing, in particular machining, a depressions (2b, 3b) in the first and second enclosure tube (2, 3), b. producing, in particular machining, the flexible spring bracket (9) with inward protrusions (90) that mate with the depressions (2b, 3b) in the first and second enclosure tube (2, 3), and c. arranging the flexible spring bracket (9) in the depressions (2b, 3b) in the first and second enclosure tube (2, 3) for connecting the first end (20) and the second end (30) and enabling limited spring loaded movement between the first end (20) and the second end (30). 31 . The method according to any one of the preceding claims 27 to 28, wherein the first enclosure tube (2) and the second enclosure tube (3) are machined to have the same inner and outer diameter, respectively.

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