Gas-tight, temperature and pressure-resistant pipe joint

Abstract

The invention relates to a pipe joint (110) for end-face, force-fitting connection of at least one pipe element (112) and at least one further element (114). The pipe element (112) is at least partially made of at least one oxide-ceramic fibre-reinforced composite material. The pipe joint (110) has at least one threaded pipe fitting (116). The threaded pipe fitting (116) has a threaded fitting body (118) which is designed to receive the pipe element (112) up to a predefined depth on a first side and to receive the further element (114) up to a predefined depth on a second side. At least one sealing element (122) is arranged between an end face and / or a lateral surface of the pipe element (112) and the threaded fitting body (118). The threaded pipe fitting (116) has at least one nut (124), wherein one element of the threaded fitting body (118) or nut (124) has an external thread and the other element of the threaded fitting body (118) or nut (124) has an internal thread. The threaded pipe fitting (116) has at least one force transmission element (130), wherein the force transmission element (130) is arranged between the pipe element (112), the threaded fitting body (118) and the nut (124) and is designed for axial force transmission to the pipe element (112) when the nut (124) is tightened.

Description

[0001] 241160W001

[0002] Gas-tight, temperature and pressure-resistant pipe connection

[0003] Description

[0004] The invention relates to a pipe connection for the end-face, force-fit connection of at least one pipe element and at least one further element, and a method for producing a connection of a pipe element and a further element using at least one pipe connection.

[0005] Types of pipe connections are known from the prior art for various applications. A problem regarding long-term leak tightness often arises with pipe connections where the pipe elements to be joined are made of different materials, especially if the pipe elements differ in their coefficients of thermal expansion. If such pipe elements are subjected to thermal stress or thermal cycling, they experience different rates of linear expansion due to their material properties, which can lead to leaks at the pipe connection or damage to the pipe elements, such as cracks.

[0006] However, the use of pipe elements made of different materials may be desirable or necessary in some applications, such as power plant engineering or chemical process engineering. For example, the use of ceramic pipe elements has proven effective in high-temperature processes, as they offer advantages over metallic materials. However, the use of ceramic pipes usually requires a connection between a metal and a ceramic pipe element – ​​with the aforementioned problems regarding the long-term sealing effect and the mechanical integrity of the connection.

[0007] Pipe connections that address the problem of differing expansion rates under heat stress are known. For example, US 2012 / 0003128 A1 describes a device for connecting a ceramic tube to a metal tube, in which a first, inner shrink ring is shrunk onto the ceramic tube and connected to the metal tube. A second, outer shrink ring, made of a material with a lower coefficient of thermal expansion than the first, is mounted on top of the first shrink ring. When the pipe connection is subjected to thermal stress by heating, the expansion of the first shrink ring is limited by the second shrink ring. While this type of connection technology is suitable for a specific temperature range and certain material combinations, 241160W001

[0008] - 2 - While suitable, it can also have disadvantages. Firstly, under high thermal stress, the inner shrink ring may expand so much, despite its outer confinement, that an annular gap forms between the ceramic tube and the inner shrink ring, causing a leak. Secondly, mounting the inner shrink ring onto the ceramic tube may require heating the ring significantly. Applying the hot shrink ring to the cool ceramic tube can cause thermal shock to the ceramic material, leading to damage or destruction.

[0009] A similar approach to connecting a ceramic tube to a metal tube is described in EP 1 795 794 A1. A hose made of an elastomeric material is pushed over the joint between the two tubes. This hose is completely enclosed by a spring band that exerts inward pressure on the elastomer. With this type of connection, too, a sufficiently high thermal load, especially strong thermal cycling, can lead to leaks, for example, due to plastic deformation of the elastomeric material. Furthermore, the application range of this tube connection is limited to a relatively low temperature range, as the elastomeric material is damaged or destroyed at high temperatures.

[0010] Further compounds are described in WO 2019 / 201654, or in PCT / EP2024 / 084471 and in German patent application no. 102024204457.1 dated May 14, 2024.

[0011] WO 2013 / 133617 describes a stainless steel pipe coupling used to connect a bronze casting socket to a stainless steel pipe. The description includes a bronze casting socket; a stainless steel ring inserted into the socket and into a band-shaped groove section located in the stainless steel pipe, with one side of the stainless steel ring open; a connecting element with a first, outwardly facing O-ring; a second O-ring into which the inside of the connecting element is inserted; a washer inserted into a nut connected to the socket; and a nut connected to the socket, with the washer placed on its inside.

[0012] WO 2013 / 085131 A1 describes a pipe fitting for joining two right and left pipes, comprising: a body positioned in the middle of the right and left pipes into which the front ends of the right and left pipes are inserted; right and left nuts, each coupled to right and left connecting sections of the body; and first and second seals for sealing between the right and left connecting sections. 241160W001

[0013] - 3 - sections, the right and left nuts, and the right and left pipes. Inclined body sections are formed on the inner diameter of the right and left connecting sections of the body, and a first front inclined sealing section of the first seal is coupled to each of the inclined body sections. Furthermore, a first inclined rear sealing section is formed on the rear of the first seal, and a second inclined front sealing section of the second seal is connected to the first inclined rear sealing section.

[0014] US 4,630,851 A describes a compression-type pipe coupling consisting of a main body with externally threaded sections, a nut, and at least one sleeve. The sleeve has a ceramic coating over its entire surface.

[0015] Despite the advantages achieved with previously known devices and methods, several technical challenges remain. For example, when using ceramic tubes with at least one other element, the problem arises of ensuring a permanent seal and the mechanical integrity of the connection.

[0016] It is therefore an object of the present invention to provide a pipe connection for the end-face, force-fit connection of at least one pipe element and at least one further element, and a method for producing a connection between a pipe element and a further element using at least one pipe connection, which at least largely avoids the disadvantages of known devices and methods. In particular, a gas-tight, temperature- and pressure-resistant, detachable pipe connection should be made possible.

[0017] This problem is solved by a pipe connection for the end-face, force-fit connection of at least one pipe element and at least one further element, and by a method for producing a connection between a pipe element and a further element using at least one pipe connection with the features of the independent claims. Preferred embodiments of the invention are specified, inter alia, in the associated dependent claims and linking claims.

[0018] In the following, the terms "have," "exhibit," "comprise," or "include," or any grammatical variations thereof, are used in a non-exclusive manner. Accordingly, these terms can refer to situations in which, besides the feature introduced by these terms, no other features are present. 241160W001

[0019] - 4 - or situations in which one or more additional features are present. For example, the expression "A has B", "A exhibits B" can 1 , “A comprises B” or “A includes B” refers both to the situation in which, apart from B, no other element is present in A (i.e., a situation in which A consists exclusively of B), and to the situation in which, in addition to B, one or more other elements are present in A, for example, element C, elements C and D, or even further elements.

[0020] Furthermore, it should be noted that the terms "at least one" and "one or more," as well as grammatical variations of these terms or similar terms, when used in connection with one or more elements or features and intended to express that the element or feature may be present once or multiple times, are generally used only once, for example, when the feature or element is first introduced. Upon subsequent mention of the feature or element, the corresponding term "at least one" or "one or more" is generally no longer used, without restricting the possibility that the feature or element may be present once or multiple times.

[0021] Furthermore, the terms "preferably," "in particular," "for example," or similar terms are used in the following text in connection with optional features without limiting alternative embodiments. Features introduced by these terms are optional features, and it is not intended that these features limit the scope of protection of the claims, and in particular the independent claims. As the person skilled in the art will recognize, the invention can also be implemented using other embodiments. Similarly, features introduced by "in one embodiment of the invention" or by "in an exemplary embodiment of the invention" are understood as optional features without limiting alternative embodiments or the scope of protection of the independent claims.Furthermore, these introductory expressions are intended to leave all possibilities of combining the features introduced herein with other features, whether optional or non-optional features, unaffected.

[0022] Measurements are referred to below using their usual abbreviations. Specifically, the units meter (m), centimeter (cm), millimeter (mm), micrometer (pm), degree Celsius (°C), pascal (Pa), gigapascal (GPa), and percent (%) are abbreviated. 241160W001

[0023] - 5 -

[0024] In a first aspect of the present invention, a pipe connection for the end-face, force-fit connection of at least one pipe element and at least one further element is proposed.

[0025] The pipe element is at least partially made of at least one oxide ceramic fiber composite material. The pipe connection includes at least one pipe fitting. The pipe fitting has a fitting body configured to receive the pipe element on one side to a predefined depth and to receive the other element on a second side to a predefined depth. At least one sealing element is arranged between an end face and / or a surface of the pipe element and the fitting body. The pipe fitting includes at least one nut. One element of the fitting body or nut has an external thread, and the other element of the fitting body or nut has an internal thread. The pipe fitting includes at least one force transmission element.The force transmission element is arranged between the pipe element, the screw body and the nut, and is designed to transmit axial force to the pipe element when the nut is tightened.

[0026] The term "pipe connection," as used here, is a broad term to which its ordinary and common meaning, as understood by those skilled in the art, should be attributed. The term is not limited to any specific or adapted meaning. Without limitation, the term can refer in particular to a composite unit consisting of a plurality of components, designed to connect at least one pipe element and at least one other element. The pipe connection can be a detachable or conditionally detachable connection. The pipe connection is force-fit.

[0027] The term "end face," as used here, is a broad term and should be understood in its ordinary and common sense, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. Without limitation, the term can refer in particular to a front or face of the end of the pipe element or other element to be joined, for example, in a plane perpendicular to a longitudinal direction of the pipe element or other element.

[0028] The term "pipe element," as used here, is a broad term to which its ordinary and common meaning, as understood by those skilled in the art, shall be attributed. The term is not limited to any specific or adapted meaning. Without limitation, the term can refer in particular to a hollow component designed to convey a fluid or gaseous medium from a first end of the pipe element to a 241160W001

[0029] - 6 - to the second end of the pipe element. The pipe element can have an interior space which is separated from an external environment by a shell surface, in particular a cylindrical shell surface. The term pipe element includes a pipeline, a part of a pipeline, a pipe segment, a pipe coil, and / or a pipe loop. The pipe element can be designed as a single pipe, a double pipe, or a multi-pipe. In the case of double pipes or multi-pipes, two or more pipe elements can be connected in parallel and supplied with a fluid or gaseous medium via a common supply and a common discharge pipeline. The pipe element can have any shape suitable for the respective application. For example, the pipe element can be straight or curved, preferably straight.

[0030] The pipe element can have a pipe diameter of 1 mm to 200 mm, preferably e mm to 51 mm.

[0031] The length of a pipe element can preferably be from 10 mm to 10000 mm, more preferably from 50 mm to 7500 mm, particularly preferably from 100 mm to 5000 mm, and especially from 200 mm to 2500 mm.

[0032] The pipe element is at least partially made of at least one oxide ceramic fiber composite material. The term "at least partially made of an oxide ceramic fiber composite material," as used here, is a broad term to which its ordinary and common meaning, as understood by those skilled in the art, should be attributed. The term is not limited to a specific or adapted meaning. Without limitation, the term can refer in particular to an embodiment of the pipe element in which the pipe element comprises an oxide ceramic fiber composite material over its entire length, especially if wrapped with OCMC, and to embodiments in which at least one region of the pipe element comprises an oxide ceramic fiber composite material, especially if wrapped with OCMC. For example, the pipe element may be partially reinforced.For example, the end of the pipe element to be joined can have an oxide ceramic fiber composite material, in particular wrapped with OCMC. The pipe element can in particular be a hybrid pipe, also referred to as a composite pipe, for example a monolithic ceramic pipe with at least the ends, in the area of ​​the connection, wrapped with OCMC. The pipe element can be a composite pipe. For example, the composite pipe can be made at least partially of monolithic ceramic, wherein the composite pipe has an oxide ceramic fiber composite material at least at one end of the composite pipe to be joined. For example, the pipe element can have at least 241160W001.

[0033] - 7 - tens in the area of ​​the force transmission element, in particular a cutting ring, shall have an oxide ceramic fiber composite material, in particular be wrapped with OCMC. One end of the pipe element, in particular in the screw body (in the fitting), may also be designed without OCMC, in particular not be reinforced.

[0034] Monolithic ceramics cannot be porous. As a rule, technical ceramic materials do not exhibit open porosity and are therefore gas-tight, as described, for example, at www.keramverband.de / brevier_dt / 5 / 3 / 5_3_2.htm. Alternatively, monolithic

[0035] Ceramics can have a porosity, for example the porosity can be 0 - 10%, preferably 0 - 7%, particularly preferably 0 - 5%.

[0036] The pipe element can be made entirely of at least one oxide ceramic fiber composite material. If an OCMC pipe element is used, i.e., the pipe element is porous, then the OCMC can be processed to make it gas-tight.

[0037] The pipe element can be made at least partially of foam ceramic. For example, at least one filter, particularly a fluid filter, can be used; for instance, fluid can be passed through a filter into a tank. The pipe element can also have at least a partial ceramic with a much higher porosity than OCMC. The porosity of fluid filters can vary considerably depending on the type and application. In general, the porosity of fluid filters, especially those used in water treatment or air filtration, typically ranges from 30% to 90%. For example, filters used for specific applications such as liquid filtration or in the chemical industry may have a porosity of approximately 30% to 60%. The filter can ensure that particles are effectively retained while still allowing sufficient flow.The specific porosity can depend on the materials used, the filter structure, and the desired degree of filtration.

[0038] The monolithic ceramic may comprise at least one material selected from the group consisting of: a binary oxide (MxOz), a mixed oxide (M1yM2vOz), a metal carbide (M3vCw), a metal nitride (M3vNw), mixtures of binary oxides (M1yOz / M2vOw, MxOz / M1yOz / M2vOw), mixtures of mixed oxides (MxMIyOz / MuM2vOw), mixtures of binary oxides and metal carbides (MxOz / M3vCw), and / or mixtures of binary oxides and metal nitrides (MxOz / M3vNw). Here, O refers to the chemical element oxygen, C to the chemical element carbon, and N to the chemical element nitrogen. 241160W001

[0039] - 8 -

[0040] M can, for example, be an element selected from the group consisting of: aluminum (Al), zirconium (Zr), silicon (Si), calcium (Ca), magnesium (Mg), beryllium (Be), yttrium (Y), lanthanum (La), iron (Fe), nickel (Ni), chromium (Cr), tungsten (W), hafnium (Hf), strontium (Sr), scandium (Sc), cerium (Ce), ytterbium (Yb). Preferably, M can be an element selected from the group consisting of: aluminum, zirconium, silicon, yttrium, lanthanum, hafnium, strontium. Particularly preferred is M aluminum, zirconium, or yttrium.

[0041] M1 can, for example, be an element selected from the group consisting of: aluminum (Al), zirconium (Zr), yttrium (Y). Preferably, M1 can be aluminum.

[0042] M2 can be, for example, an element selected from the group consisting of: Zirconium (Zr), Silicon (Si), Magnesium (Mg), Yttrium (Y), Titanium (Ti).

[0043] M3 can, for example, be an element selected from the group consisting of: aluminum (Al), silicon (Si), boron (B), tungsten (W). x, y, z, u, v and w can each be independently between 1 and 10, preferably between 1 and 7 and particularly preferably between 1 and 5.

[0044] For example, the ceramic material may contain at least one mixture selected from the group consisting of: binary and ternary mixtures of aluminum oxide (Al₂O₃), zirconium oxide (ZrÜ₂) and yttrium oxide (Y₂O₃) (e.g.Zirconium oxide-reinforced aluminum oxide; mixtures of silicon carbide (SiC) and aluminum oxide; mixtures of aluminum oxide and magnesium oxide (MgO spinel); mixtures of aluminum oxide and silicon oxide (mullite); mixtures of aluminum silicates and magnesium silicates, ternary mixtures of aluminum oxide, silicon oxide and magnesium oxide (cordierite); steatite (magnesium silicate); zirconium oxide-reinforced aluminum oxide; stabilized zirconium oxide: stabilizers in the form of magnesium oxide (MgO), calcium oxide (CaO) or yttrium oxide, optionally cerium oxide (CeO₂), scandium oxide (ScO₃) or ytterbium oxide (YbO₃) are also used as stabilizers; furthermore, aluminum titanate (stoichiometric mixture of aluminum oxide and titanium oxide, AhO₃ / TiO₂); silicon nitride and aluminum oxide (silicon aluminum oxynitrides).

[0045] Zirconium oxide-reinforced aluminum oxide, for example, Al₂O₃ with 10 to 20 mol% ZrÜ₂, can be used. For stabilization of ZrÜ₂, for example, 10 to 20 mol%, preferably 16 mol% CaO, 10 to 20 mol%, preferably 16 mol% MgO, or 5 to 10 mol% Y₂O₃, preferably 8 mol% Y₂O₃ ("fully stabilized zirconium oxide"), or 1 to 5 mol% Y₂O₃, preferably 4 241160W001, can be used.

[0046] - 9 -

[0047] Mol-% ("partially stabilized zirconium oxide") can be used. For example, a ternary mixture of 80% Al₂O₃, 18.4% ZrC>2, and 1.6% Y₂O₃ can be used.

[0048] For example, the ceramic material can be selected from the group consisting of quartz glass (SiO2), silicon carbide (SiC), silicon nitride (Sisl^ ), aluminium nitride (AlN), corundum (Al2O3), zirconia (ZrO2), mullite or fiber composites based on these components.

[0049] The ceramic material may also include a composite material, for example a composite material made of several layers of monolithic ceramic and / or oxide fiber composite ceramic, as described, for example, in documents WO 2016 / 184776 A1 or EP 3 835 639 A1.

[0050] The terms “composite material” and “fiber-reinforced composite material,” as used here, are broad terms to which their ordinary and common meanings, as understood by those skilled in the art, shall be attributed. The terms are not limited to any specific or adapted meaning. Without limitation, the terms can refer in particular to any material made from two or more components. These components may have distinctly different chemical or physical properties and may be fused together to form a material with properties that differ from those of the individual materials. Within the composite material, the individual materials may remain separate.

[0051] The term "fiber composite material" 1The term "fiber-reinforced composite," as used here, is a broad term to which its ordinary and common meaning, as understood by those skilled in the art, should be attributed. The term is not limited to any specific or adapted meaning. In particular, the term can, without limitation, refer to any material that generally comprises at least two principal components: reinforcing fibers and an embedding matrix that may act as a filler and / or adhesive between the fibers. Mutual interactions between the two components can confer higher-value properties on the overall material than either component alone. The fiber-reinforced composite may, in particular, comprise the fibers as a discontinuous or dispersed phase, the matrix as a continuous phase, and an intermediate phase region, which may also be referred to as an interface.

[0052] The term “ceramic matrix composite” (“CMC”), as used here, is a broad term and should be interpreted according to its usual and common meaning as understood by those skilled in the art. The term is not limited to a 241160W001

[0053] - 10 - special or adapted meaning. The term can, without limitation, refer in particular to any composite material, especially any fiber-reinforced composite comprising a variety of ceramic fibers embedded in a ceramic matrix. In this context, carbon and carbon fibers can also be considered ceramic materials.

[0054] The term “oxide ceramic matrix composite” (“OCMC”), as used here, is a broad term and should be interpreted according to its usual and common meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. Without limitation, the term can refer in particular to any ceramic matrix composite comprising an oxide ceramic matrix reinforced by oxide ceramic reinforcing fibers. OCMCs can be fiber-reinforced composites comprising a fiber framework embedded in a porous oxide ceramic matrix. The term “OCMC” can refer to structures with a purely ceramic fiber framework or to structures whose fiber framework comprises, in addition to ceramic fibers, fibers made of at least one other material, e.g., metal fibers.

[0055] The oxide ceramic fiber composite can comprise at least one oxide ceramic matrix. The oxide ceramic matrix can be selected from the group consisting of SixMyOz, Si x M1yM2 w Oz, Si x ByN z Cw, AIN, M x O y and mixed oxides of the form (M1 x Oy / M2 w Oz). The oxide fiber composite may have a fiber framework of ceramic fibers. The ceramic fibers may comprise at least one material selected from the group consisting of: mullite, Al₂O₃, a combination of mullite and Al₂O₃.

[0056] The oxide fiber composite can, for example, contain at least one element selected from the group consisting of: SiC / AhOs, SiC / Mullit, C / AhO3, C / Mullit, Al₂O3 / Al₂O3, Al₂O3 / Mullit, Mullite / AhOs, and / or Mullite / Mullit. The designation of the fiber composites is based on the notation used, for example, in Walter EC Pritzkow, Frank Wehner, Dietmar Koch, Oxide Fiber Reinforced Oxide Ceramic Matrix Composite - An Alternative to Metallic Alloys at High Temperature, Editor(s): Francisca G. Caballero, Encyclopedia of Materials: Metals and Alloys, Elsevier, 2022, Pages 425-441: In the designation A / B, “A” denotes the composition of the fiber framework, and “B” denotes the composition of the matrix. 241160W001

[0057] - 11 -

[0058] Advantages of such OCMCs include high temperature resistance up to 1300 °C or more in oxidizing or reducing atmospheres, high thermal shock resistance, and quasi-ductile deformation and fracture behavior. The open porosity (E) of fiber-reinforced ceramics typically ranges from 5% to 50%. The fracture toughness of OCMCs can reach values ​​of 10–50 MPa / m. Due to their porous structure, fiber-reinforced ceramics can exhibit lower density, lower modulus of elasticity, and lower thermal conductivity compared to monolithic ceramics with the same chemical composition.

[0059] The following table contains a list of the relevant standards for determining these parameters, in particular a list of the relevant standards for determining the structural, mechanical and thermophysical parameters for monolithic ceramics and for OCMC.

[0060] The additional element may comprise at least one element selected from the group consisting of: a composite tube, which is at least partially made of monolithic ceramic and has an oxide ceramic fiber composite material at least at one end of the composite tube to be joined; a metallic tube; a plastic element, in particular a hose; a glass element; an apparatus. For example, the apparatus may be a boiler, columns, reactors, and others.

[0061] The pipe connection has at least one pipe coupling. The term "pipe coupling", also referred to as fitting or valve, as used here, is a broad term, 241160W001

[0062] - 12 - to which its ordinary and common meaning is to be attributed, as understood by a person skilled in the art. The term is not limited to a special or adapted meaning. The term can, without limitation, refer in particular to a component which is designed to make a connection and / or to join the pipe element to at least one other element. The pipe fitting can be a connecting piece.

[0063] The pipe fitting has a fitting body. The term "fitting body," as used here, is a broad term to which its ordinary and common meaning, as understood by those skilled in the art, should be attributed. The term is not limited to any specific or adapted meaning. Without limitation, the term can refer in particular to a body or base of the pipe fitting, which provides a receptacle for at least the pipe element and the additional element. The fitting body can be configured to completely encircle the pipe element and the additional element in the circumferential direction and at least partially in the longitudinal direction. The fitting body is configured to receive the pipe element on one side to a predefined depth and to receive the additional element on a second side to a predefined depth.

[0064] The term "to receive the pipe element to a predefined depth," as used here, is a broad term to which its ordinary and common meaning, as understood by a person skilled in the art, should be attributed. The term is not limited to any specific or adapted meaning. Without limitation, the term can refer in particular to the relative positioning of the pipe element and the fitting body. This relative positioning can include inserting the pipe element into the fitting body until it reaches a stop and / or screwing the pipe element into the fitting body using a thread.

[0065] The term “to accommodate the further element to a predefined depth,” as used here, is a broad term to which its ordinary and common meaning, as understood by a person skilled in the art, should be attributed. The term is not limited to any special or adapted meaning. Without limitation, the term can refer in particular to a relative positioning of the further element and the fitting body. For example, the further element can be inserted and / or screwed into the fitting body. For example, the fitting body can be inserted into the further element, in particular by welding, and / or screwed into it. (See 241160W001)

[0066] - 13 -

[0067] The side of the screw body for receiving the additional element may have an internal or external thread, or no thread at all.

[0068] The fitting body can be designed, at least partially, as a hollow body into which the pipe element and the other element can be inserted, for example, by being inserted and / or screwed in. The fitting body can have a stop against which the respective end faces of the pipe element and the other element can abut. The stop can define the predefined depth. The fitting body can have an inner wall, in particular an unthreaded inner wall or a threaded inner wall. For example, the fitting body can be designed as a screw-in type. The thread can define the predefined depth. The term "thread," as used here, is a broad term to which its ordinary and common meaning, as understood by those skilled in the art, should be attributed. The term is not limited to a specific or adapted meaning.The term can, without limitation, refer in particular to a profiled groove that runs continuously in a helical fashion in a cylindrical inner or outer wall. The thread can, in particular, be an internal thread, i.e., running in an inner wall, and accommodate a body with a mating thread. The thread can be right-handed or left-handed. The fitting body can further have at least one external thread, in particular on a side of the fitting body facing away from the pipe element.

[0069] The pipe fitting, in particular the fitting body, can be a straight pipe fitting, a cross, an angle, or a tee.

[0070] The additional element can be connected to the pipe fitting by at least one weld-in or screw-in fitting.

[0071] At least one sealing element is arranged between an end face and / or a lateral surface of the pipe element and the fitting body. If the end of the pipe element to be joined is reinforced with OCMC, the sealing element can be arranged between the end face of the pipe element and the fitting body. For example, the pipe element can have an oxide ceramic fiber composite material, particularly wrapped with OCMC, at least in the area of ​​the force transmission element, especially a cutting ring. One end of the pipe element, particularly in the fitting body, can also be designed without OCMC, and in particular, may not be reinforced. In this case, instead of or in addition to an end-face arrangement of the sealing element, a sealing element can be used which is arranged over the circumference of the pipe element 241160W001.

[0072] - 14 - seals, e.g., an O-ring. The term "sealing element," as used here, is a broad term to which its ordinary and common meaning, as understood by those skilled in the art, shall be attributed. The term is not limited to any specific or adapted meaning. The term can, without limitation, refer in particular to a one-piece or multi-piece device designed to seal at least one opening, for example, at least one gap.

[0073] The pipe connection, in particular the sealing element, can be designed to connect the pipe element and the other element in a fluid-conducting and / or gas-tight and technically tight manner.

[0074] In particular, the sealing element can be designed to prevent the passage of a fluid or gas into a joint or gap between the fitting body and the pipe element. Specifically, the sealing element can be configured to seal the joint or gap fluidically and / or gas-tight, so that no fluid or gas can pass into the gap or joint. The sealing element can, in particular, seal joints or gaps that occur at connections between the fitting body and the pipe element. The sealing element can be arranged between the end face of the pipe element and the stop of the fitting body. The sealing element can be configured to provide a gas-tight connection between the fitting body and the pipe element. The term "gas-tight," as used here, is a broad term and should be understood to have its usual and common meaning as understood by those skilled in the art.The term is not limited to a specific or adapted meaning. Without restriction, the term can refer in particular to a leakage rate of 0.01 g / (h*m), as described, for example, in the DGMK working group "Leakage rates of sealing elements". Petroleum, Coal. Petrochem. (1982) No. 12, Synopsis 82-00.

[0075] The term "technically leak-tight," as used here, is a broad term to which its usual and common meaning, as understood by those skilled in the art, should be attributed. The term is not limited to any specific or adapted meaning. Without limitation, the term can refer in particular to a compound from which no releases are to be expected. "Technically leak-tight" refers in particular to permanently leak-tightness in accordance with TRGS 722 "Prevention or Limitation of Hazardous Explosive Mixtures," version 14.3.2022, pages 11 to 13 of 33.

[0076] The sealing element can have at least one element selected from the group consisting of: a flat gasket, a stuffing box gasket, a lens gasket, an O-ring 241160W001

[0077] - 15 -

[0078] The end seal is a metal gasket. The choice of sealing element can depend on the process and process conditions. For example, the sealing element can be a flat graphite gasket. The pipe fitting can be designed to have a flat surface on the inside, particularly to allow the flat gasket to act effectively. When using a standard fitting, this may involve post-processing of the pipe fitting.

[0079] The pipe connection can be configured to provide a temperature-resistant connection within a temperature range of -200°C to 600°C, preferably -40°C to 200°C. The pipe connection can be used, for example, for burner lances in steam crackers or reformers. Another example is the connection of high-temperature reactors (e.g., reformer tubes) to the periphery.

[0080] The pipe fitting has at least one nut. The term "nut," as used here, is a broad term and should be understood in its usual and common sense, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. Without limitation, the term can refer in particular to a fastening element or part of a fastening element that can functionally interact with the fitting body to form a screw connection. The nut may have an internal thread and, in particular, be screwable onto an external thread of the fitting body. The nut may be a union nut. Alternatively or additionally, the nut may have an external thread, also referred to as a nut, which can be screwed onto the fitting body.For example, in the case of a nut, the force transmission element can be positioned in front of the nut and pressed against the screw body when the nut is tightened.

[0081] The pipe fitting has at least one force transmission element. The term "force transmission element," as used here, is a broad term and should be understood in its usual and common sense, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. Without limitation, the term can refer in particular to an element or component that transmits axial forces to the pipe element when the nut is tightened during the connection of the fitting body and the nut. The force transmission element can be arranged on an outer circumference of the pipe element. Through the possibility of axial force transmission, the pipe element can permanently press the sealing element against the stop of the 241160W001.

[0082] - 16 -

[0083] Pipe coupling press. The force transmission element can have at least one element selected from the group consisting of: at least one clamping ring; at least one cutting ring; at least one stop.

[0084] The power transmission element, in particular the cutting ring, can become embedded in the OCMC during tightening, especially with a predefined torque and / or tightening angle, and in particular only in the OCMC. The actual ceramic tube may remain unaffected. The power transmission element, in particular the cutting ring, cannot become embedded in the ceramic tube during tightening, so it will not deform. If the predefined torque and / or tightening angle is exceeded, the cutting ring can also strike the ceramic tube and damage the tube element. Therefore, proper pre-assembly and assembly must be ensured. Unlike conventional metal tubes, the ceramic tube is brittle, so damage will cause the ceramic tube to break.A connection using a ceramic tube is therefore fundamentally different from a connection using a metal tube.

[0085] WO 2013 / 133617 and WO 2013 / 085131 A1 describe circumferential sealing using O-rings. Such seals are unsuitable for pipe connections for the end-face, force-fit connection of the pipe element and the further element as a force transmission element. WO 2013 / 133617 and WO 2013 / 085131 A1 propose sealing at an outer area, which for the pipe connection according to the invention would be at the location of the OCMC. This is not possible. Anything that seals circumferentially is unsuitable for the application according to the invention. According to the invention, the sealing function is ensured by means of the sealing element, while the force transmission element does not need to have a sealing function. US 4,630,851 A describes a standard metal pipe connector. The pipe in US 4,630,851 A is deformed. In the case of a ceramic pipe, this would mean a defective pipe. The pipe connection according to the invention can also reduce working time compared to known connections.The aforementioned documents also describe a tightness against liquids (water). According to the invention, the tightness requirement is significantly higher (gas).

[0086] For example, the force transmission element can be at least one clamping and / or cutting ring. The clamping ring can be arranged flat against an outer wall of the pipe element and pressed onto the outer wall when the nut is tightened. The clamping and / or cutting ring can be made of at least one metallic material selected from the group consisting of: copper, stainless steel 316, carbon steel, brass, aluminum, Monel, 241160W001

[0087] - 17 -

[0088] Hastelloy C®, Incolloy, Titanium, 6Mo, Alloy 617, Alloy 625, Alloy 400, Alloy C-276, Alloy 600, Alloy 825, Alloy C-22, Alloy 690, Alloy 718, Alloy X-750, Waspalloy, Rene 41, the following materials listed in DIN EN 10095:1999 “Heat-resistant steels and nickel alloys” 1.4713, 1.4724, 1.4742, 1.4762, 1.4749, 1.4737, 1.4878, 1.4828, 1.4835, 1.4833, 1.4845, 1.4841, 1.4864, 1.4876, 1.4877, 1.4872, 1.4818, 1.4854, 1.4886, 1.4887, 1.4821, 1.4512, 1.4510, 1.4509, 1.4301, 1.4948, 1.4541, 1.4941, 1.4950, 1.4951, 1.4362, the following materials listed in DIN EN 10028-2:2017 "Flat products of pressure vessel steels - Part 2: Unalloyed and alloyed steels with specified elevated temperature properties" 1.0345, 1.0425, 1.0481, 1.0473, 1.5415, 1.5414, 1.6311, 1.6368, 1.7335, 1.7336, 1.7380, 1.7375, 1.7362, 1.7703, 1.7767, 1.4903, stainless steel 304, nylon, PFA and PTFE. For example, the force transmission element can be a copper clamping ring.For example, the force transmission element can be a steel or brass cutting ring. The pipe connection can, for example, have two force transmission elements, such as two clamping and / or cutting rings. The two clamping and / or cutting rings can be designed as a front clamping ring and a rear cutting ring, with at least the rear cutting ring cutting into the pipe element and being responsible for the force transmission in the axial direction, for pressing the sealing element.

[0089] For example, the force transmission element can have at least one stop made of an oxide ceramic fiber composite material. The stop can be an OCMC ring with a sufficiently large diameter for the pipe element. To allow the nut to be attached, the pipe element can be fitted with an OCMC stop on only one side, so that the nut can be mounted from the other side.

[0090] Pipe fittings are a standard for connecting metallic pipes. However, for a pipe element that is at least partially made of at least one oxide ceramic fiber composite material, it is expected that these pipe fittings would be unsuitable for connecting the pipe element to another element and would destroy the pipe. Furthermore, the oxide ceramic composite material itself is a porous structure, so sealing cannot be achieved using known pipe fittings. Surprisingly, it has been found that pipe fittings can be used for a gas-tight, pressure-resistant, and temperature-resistant connection of a pipe element that is at least partially made of at least one oxide ceramic fiber composite material to another element. Since the oxide ceramic composite material itself is a porous structure, the invention proposes that the sealing is achieved via the end face of the pipe element.For example, a (flat) gasket can be inserted between the end face and the fitting. The axial force transmission for pressing the gasket can be achieved using a union nut and a force transmission element, 241160W001.

[0091] - 18 - which is arranged on the outer circumference of the pipe element. The force transmission element can be, for example, a metal cutting ring or an OCMC ring with a correspondingly large diameter. Surprisingly, the use of standardized pipe fittings for connecting a pipe element, at least partially made of at least one oxide ceramic fiber composite material, to another element is therefore possible.

[0092] In a further aspect, the present invention proposes a method for producing a connection between a pipe element, at least partially made of at least one oxide ceramic fiber composite material, and another element using at least one pipe connection according to the invention. For the design and definitions of the method, reference is made to the description of the pipe connection above or below.

[0093] The process steps can be carried out in the specified order, whereby one or more of the steps can be performed simultaneously, at least partially, and where one or more of the steps can be repeated multiple times. Furthermore, additional steps can be performed, regardless of whether they are mentioned in this description or not.

[0094] The procedure comprises the following steps: i. Providing the pipe element and the additional element and positioning the pipe element and the additional element relative to the pipe fitting; ii. Pre-assembly by force-fit connection of the pipe element and the force transmission element by tightening the nut; iii. Optionally, loosening the nut and removing the pipe element from the pipe fitting, and inserting the sealing element into the pipe fitting; iv. Force-fit connection of the pipe element and the pipe fitting by tightening the nut; v. Connecting the pipe fitting to the additional element.

[0095] Pre-assembly can include a force-fit connection of the pipe element and the force transmission element before inserting the sealing element by tightening the nut. In this step, the cutting ring can work its way into the OCMC layer of the pipe element. After pre-assembly, to create the connection between the pipe element, which is at least partially made of at least one oxide ceramic fiber composite material, and the white- 241160W001

[0096] - 19 - The nut on the other element must be loosened and the pipe element removed from the pipe fitting. During pre-assembly without using the sealing element, the position of the cutting ring can be determined. If the seal is subsequently inserted during the connection process, e.g., with a thickness of 2 mm, then there is a space, e.g., 2 mm, to compress the seal by tightening the nut.

[0097] Steps ii. and iii. can be performed in a different order. The sealing element can be inserted during pre-assembly, particularly before tightening the nut. For example, one sealing element can be inserted during pre-assembly, and then another sealing element can be added during assembly to create the connection. The sealing element used during assembly can also be thicker. The pre-assembly device can be designed differently with regard to the penetration depth of the OCMC tube. Other embodiments are also conceivable.

[0098] In summary, the following embodiments are particularly preferred within the scope of the present invention:

[0099] Embodiment 1. Pipe connection for end-face, force-fit connection of at least one pipe element and at least one further element, wherein the pipe element is at least partially made of at least one oxide ceramic fiber composite material, wherein the pipe connection has at least one pipe screw fitting, wherein the pipe screw fitting has a screw body which is configured to receive the pipe element on a first side to a predefined depth and to receive the further element on a second side to a predefined depth, wherein at least one sealing element is arranged between an end face and / or a lateral surface of the pipe element and the screw body, wherein the pipe screw fitting has at least one nut, wherein one element of the screw body or nut has an external thread and the other element of the screw body or nut has an internal thread.wherein the pipe wrench has at least one force transmission element, wherein the force transmission element is arranged between the pipe element, the screw body and the nut and is designed to transmit axial force to the pipe element when the nut is tightened.

[0100] Embodiment 2. Pipe connection according to the preceding embodiment, wherein the force transmission element comprises at least one element selected from the group consisting of: at least one clamping ring; at least one cutting ring; at least one stop. 241160W001

[0101] - 20 -

[0102] Embodiment 3. Pipe connection according to the preceding embodiment, wherein the force transmission element is at least one clamping and / or cutting ring, wherein the clamping and / or cutting ring is made of at least one metallic material selected from the group consisting of: copper, stainless steel 316, carbon steel, brass, aluminum, Monel, Hastelloy C®, Incolloy, titanium, 6Mo, Alloy 617, Alloy 625, Alloy 400, Alloy C-276, Alloy 600, Alloy 825, Alloy C-22, Alloy 690, Alloy 718, Alloy X-750, Waspalloy, Rene 41, the following materials listed in DIN EN 10095:1999 “Heat-resistant steels and nickel alloys” 1.4713, 1.4724, 1.4742, 1.4762, 1.4749, 1.4737, 1.4878, 1.4828, 1.4835, 1.4833, 1.4845, 1.4841, 1.4864, 1.4876, 1.4877, 1.4872, 1.4818, 1.4854, 1.4886, 1.4887, 1.4821, 1.4512, 1.4510, 1.4509, 1.4301, 1.4948, 1.4541, 1.4941, 1.4950, 1.4951, 1.4362, the following materials listed in DIN EN 10028-2:2017 “Flat products of pressure vessel steels - Part 2: Unalloyed and alloyed steels with specified elevated temperature properties” 1.0345, 1.0425, 1.0481, 1.0473, 1.5415, 1.5414, 1.6311, 1.6368, 1.7335, 1.7336, 1.7380, 1.7375, 1.7362, 1.7703, 1.7767, 1.4903, stainless steel 304, nylon, PFA and PTFE.

[0103] Embodiment 4. Raw connection according to one of the two preceding embodiments, wherein the force transmission element has two clamping rings.

[0104] Embodiment 5. Pipe connection according to embodiment 2, wherein the force transmission element has at least one stop which is made of an oxide ceramic fiber composite material.

[0105] Embodiment 6. Pipe connection according to one of the preceding embodiments, wherein the oxide ceramic fiber composite material comprises at least one oxide ceramic matrix, wherein the oxide ceramic matrix is ​​selected from the group consisting of SixMyOz, Si x M1yM2 w Oz, Si x ByN z Cw, AIN, M x O y and mixed oxides of the form (M1 x Oy / M2 w Oz), wherein the oxide ceramic fiber composite material has a fiber framework of ceramic fibers, wherein the ceramic fibers comprise at least one material selected from the group consisting of: mullite, Al2O3, a combination of mullite and Al2O3.

[0106] Embodiment 7. Pipe connection according to one of the preceding embodiments, wherein the pipe element is a composite pipe, wherein the composite pipe is at least partially made of monolithic ceramic, wherein the composite pipe is at least at one point. 241160W001

[0107] - 21 - connecting end of the composite pipe has an oxide ceramic fiber composite material.

[0108] Embodiment 8. Pipe connection according to one of the preceding embodiments, wherein the further element comprises at least one element selected from the group consisting of: a composite pipe which is at least partially made of monolithic ceramic and has an oxide ceramic fiber composite material at least at one end of the composite pipe to be joined; a metallic pipe, a plastic element, in particular a hose; a glass element; an apparatus.

[0109] Embodiment 9. Pipe connection according to one of the preceding embodiments, wherein the further element is connected to the pipe fitting by at least one weld-in or screw-in fitting.

[0110] Embodiment 10. Pipe connection according to one of the preceding embodiments, wherein the pipe element has a pipe diameter of 1 mm to 200 mm, preferably e mm to 51 mm.

[0111] Embodiment 11. Pipe connection according to one of the preceding embodiments, wherein the pipe screw fitting, in particular the screw body, comprises a straight pipe screw fitting, a cross fitting, an angle fitting, or a tee fitting.

[0112] Embodiment 12. Pipe connection according to one of the preceding embodiments, wherein the pipe connection is a detachable connection.

[0113] Embodiment 13. Pipe connection according to one of the preceding embodiments, wherein the pipe connection is gas-tight and pressure-resistant at temperatures from -200°C to 600°C, preferably -40°C to 200°C.

[0114] Embodiment 14. Pipe connection according to one of the preceding embodiments, wherein the pipe connection is arranged to connect the pipe element and the further element in a fluid-conducting and / or gas-tight and technically tight manner.

[0115] Embodiment 15. Pipe connection according to one of the preceding embodiments, wherein the sealing element comprises at least one element from the group consisting of: a flat gasket, a gland gasket, a lens gasket, an O-ring end gasket, a metal gasket. 241160W001

[0116] - 22 -

[0117] Embodiment 16. Method for producing a connection between a pipe element, at least partially made of at least one oxide ceramic fiber composite material, and a further element using at least one pipe connection according to one of the preceding embodiments, comprising the steps: i. Providing the pipe element and the further element and positioning the pipe element and the further element relative to the pipe fitting; ii. Pre-assembling by frictionally connecting the pipe element and the force transmission element by tightening the nut; iii. Inserting the sealing element into the pipe fitting; iv. Frictionally connecting the pipe element and the pipe fitting by tightening the nut; v. Connecting the pipe fitting to the further element.

[0118] Brief description of the characters

[0119] Further details and features of the invention will become apparent from the following description of preferred embodiments, particularly in conjunction with the dependent claims. The respective features can be implemented individually or in combination with one another. The invention is not limited to these embodiments. The embodiments are shown schematically in the figures. Identical reference numerals in the individual figures denote identical or functionally equivalent elements, or elements that correspond to one another with respect to their functions.

[0120] Specifically, we show:

[0121] Figure 1 shows a sectional drawing of an exemplary embodiment of a pipe connection according to the invention for the end-face, force-fit connection of at least one pipe element and at least one further element;

[0122] Figure 2 shows a sectional drawing of a further exemplary embodiment of a pipe connection according to the invention for the end-face, force-fit connection of at least one pipe element and at least one further element;

[0123] Figure 3 shows a sectional drawing of a further exemplary embodiment of a pipe connection according to the invention for the end-face, force-fit connection of at least one pipe element and at least one further element; 241160W001

[0124] - 23 -

[0125] Figure 4 shows a sectional drawing of a further exemplary embodiment of a pipe connection according to the invention for the end-face, force-fit connection of at least one pipe element and at least one further element; and

[0126] Figure 5 is a section of Figure 1 in the assembled state.

[0127] Examples of implementation

[0128] Figure 1 shows a schematic representation of an exemplary embodiment of a pipe connection 110 according to the invention for the end-face, force-fit connection of at least one pipe element 112 and at least one further element 114. The pipe connection 110 can be a detachable or conditionally detachable connection. The pipe connection 110 is force-fit.

[0129] The pipe element 112 can be configured to convey a fluid or gaseous medium from a first end of the pipe element 112 to a second end of the pipe element 112. The pipe element 112 can have an interior space which is separated from an external environment by a shell surface, in particular a cylindrical shell surface. The pipe element 112 can have any shape suitable for the intended application. For example, the pipe element 112 can be straight or curved, preferably straight. The pipe element 112 can have a pipe diameter of 1 mm to 200 mm, preferably 6 mm to 51 mm. The length of a pipe element 112 can preferably be from 10 mm to 10,000 mm, more preferably from 50 mm to 7,500 mm, and particularly preferably from 100 mm to 5,000 mm, especially from 200 mm to 2,500 mm.

[0130] The pipe element 112 is at least partially made of at least one oxide ceramic fiber composite material. For example, the pipe element 112 can have an oxide ceramic fiber composite material over its entire length, in particular wrapped with OCMC. For example, the pipe element, in particular at least the end of the pipe element 112 to be joined, can have an oxide ceramic fiber composite material. The pipe element 112 can in particular be a hybrid pipe, for example a monolithic ceramic pipe with OCMC wrapped at least at the ends, in particular in the area of ​​the pipe joint. 241160W001

[0131] - 24 -

[0132] The further element 114 may comprise at least one element selected from the group consisting of: a composite tube, which is at least partially made of monolithic ceramic and has an oxide ceramic fiber composite material at least at one end of the composite tube to be joined; a metallic tube; a plastic element, in particular a hose; a glass element; an apparatus. For example, the apparatus may be a boiler, columns, reactors and others.

[0133] The pipe connection 110 has at least one pipe coupling 116. The pipe coupling 116 has a coupling body 118. The coupling body 118 can provide a receptacle for at least the pipe element 112 and the additional element 114. The coupling body 118 can be configured to fully encircle the pipe element 112 and the additional element 114 circumferentially and at least partially longitudinally. The coupling body 118 is configured to receive the pipe element 112 to a predefined depth on one side and the additional element 114 to a predefined depth on a second side. The coupling body 118 can be designed, at least partially, as a hollow body into which the pipe element 112 and the additional element 114 can be inserted, for example, by being inserted and / or screwed in.The screw body 118 can have a stop 120 against which the respective end face of the pipe element 112 and the further element 114 can abut. The stop 120 can define the predefined depth. The screw body 118 can have an inner wall, in particular a threadless inner wall or an inner wall with threads. For example, the screw body can be designed as a screw-in fitting. The thread can define the predefined depth. The thread can, in particular, be an internal thread, i.e., run in an inner wall, and accommodate a body with a mating thread. The thread can be right-handed or left-handed. The pipe fitting 116, in particular the screw body 118, can be a straight pipe fitting, a cross fitting, an elbow fitting, or a tee fitting.

[0134] At least one sealing element 122 is arranged between an end face of the pipe element 112 and the screw body 118. The pipe connection 110, in particular the sealing element 122, can be configured to connect the pipe element 112 and the further element 114 in a fluid-conducting and / or gas-tight and technically leak-tight manner. The sealing element 122 can comprise at least one element selected from the group consisting of: a flat gasket, a gland gasket, a lens gasket, an O-ring end gasket, or a metal gasket. The selection of the sealing element 122 may depend on the process and process conditions. For example, the sealing element 122 can be a flat gasket made of graphite. The pipe connection 241160W001

[0135] - 25 - The screw fitting 116 can be designed such that it has a flat surface inside, in particular to allow the flat seal to function. When using a standard fitting, this may include, in particular, post-processing of the pipe screw fitting 116.

[0136] The pipe connection 110 can be configured to provide a temperature-resistant connection in a temperature range of -200°C to 600°C, preferably -40°C to 200°C. The pipe connection can be used, for example, for burner lances in steam crackers or reformers. Another example is the connection of high-temperature reactors (e.g., reformer tubes) to the periphery.

[0137] The pipe fitting 116 has at least one nut 124. The nut can have an internal thread 126 and, in particular, can be screwed onto an external thread 128 of the fitting body 118. The nut 124 can be a union nut, as shown in Figure 1.

[0138] The pipe fitting 116 has at least one force transmission element 130. The force transmission element 130 can be configured to transmit axial forces occurring when the nut 124 is tightened during the connection of the fitting body 118 and the nut 124 to the pipe element 112. The force transmission element 130 can be arranged on an outer circumference of the pipe element 112. This axial force transmission allows the pipe element 112 and the sealing element 122 to be permanently pressed against the stop 120 of the pipe fitting 116.

[0139] The force transmission element 130 can comprise at least one element selected from the group consisting of: at least one clamping ring; at least one cutting ring; at least one stop. In the embodiment shown in Figure 1, the pipe wrench 116 has two force transmission elements 130, for example, two clamping and / or cutting rings. The two clamping and / or cutting rings can be configured as a front clamping ring 132 and a rear cutting ring 134, wherein at least the rear cutting ring 134 cuts into the pipe element 112 and is responsible for the force transmission in the axial direction, for pressing the sealing element 122.The clamping and / or cutting rings may be made of at least one metallic material selected from the group consisting of: copper, stainless steel 316, carbon steel, brass, aluminum, Monel, Hastelloy C®, Incolloy, titanium, 6Mo, Alloy 617, Alloy 625, Alloy 400, Alloy C-276, Alloy 600, Alloy 825, Alloy C-22, Alloy 690, Alloy 718, Alloy X-750, Waspalloy, Rene 41, the following materials listed in DIN EN 10095:1999 “Heat-resistant steels and nickel alloys” 1.4713, 1.4724, 1.4742, 1.4762, 1.4749, 241160W001.

[0140] - 26 -

[0141] 1.4737, 1.4878, 1.4828, 1.4835, 1.4833, 1.4845, 1.4841, 1.4864, 1.4876, 1.4877, 1.4872, 1.4818, 1.4854, 1.4886, 1.4887, 1.4821, 1.4512, 1.4510, 1.4509, 1.4301, 1.4948, 1.4541, 1.4941, 1.4950, 1.4951, 1.4362, the following materials are listed in DIN EN 10028-2:2017 "Flat products made of pressure vessel steels - Part 2: Unalloyed and alloyed steels with specified elevated temperature properties” 1.0345, 1.0425, 1.0481, 1.0473, 1.5415, 1.5414, 1.6311, 1.6368, 1.7335, 1.7336, 1.7380, 1.7375, 1.7362, 1.7703, 1.7767, 1.4903, stainless steel 304, nylon, PFA and PTFE. For example, the clamping ring 132 can be a copper clamping ring.

[0142] The additional element 114 can be connected to the pipe fitting 116 by at least one weld-in or screw-in fitting. Furthermore, embodiments are conceivable in which the weld-in or screw-in fitting is already integrated into the pipe fitting 116. In Figure 1, the additional element 114 is inserted into the fitting body 118 and sealed by means of a union nut and two clamping rings.

[0143] Figure 2 shows another embodiment of the pipe connection 110. For the description of Figure 2, reference can largely be made to Figure 1. The following discussion focuses only on the differences compared to Figure 1. In this embodiment, the force transmission element 130 can have at least one stop 136, for example, the stop 136 can be made of at least one metallic material selected from the group consisting of: copper, stainless steel 316, carbon steel, brass, aluminum, Monel, Hastelloy C®, Incolloy, titanium, 6Mo, Alloy 617, Alloy 625, Alloy 400, Alloy C-276, Alloy 600, Alloy 825, Alloy C-22, Alloy 690, Alloy 718, Alloy X-750, Waspalloy, Rene 41, the following materials listed in DIN EN 10095:1999 “Heat-resistant steels and nickel alloys” 1.4713, 1.4724, 1.4742, 1.4762, 1.4749, 1.4737, 1.4878. 1.4828, 1.4835, 1.4833, 1.4845, 1.4841, 1.4864, 1.4876, 1.4877, 1.4872, 1.4818, 1.4854, 1.4886, 1.4887, 1.4821, 1.4512, 1.4510, 1.4509, 1.4301, 1.4948, 1.4541, 1.4941, 1.4950, 1.4951, 1.4362, the following materials listed in DIN EN 10028-2:2017 "Flat products of pressure vessel steels - Part 2: Unalloyed and alloyed steels with specified elevated temperature properties" 1.0345, 1.0425, 1.0481, 1.0473, 1.5415, 1.5414, 1.6311, 1.6368, 1.7335, 1.7336, 1.7380, 1.7375, 1.7362, 1.7703, 1.7767, 1.4903, stainless steel 304, nylon, PFA and PTFE. In the embodiment shown in Figure 2, the sealing element 122 can have at least one O-ring.

[0144] Figure 3 shows another embodiment of the pipe connection 110. For the description of Figure 3, reference can largely be made to Figure 1. The following discussion focuses only on differences from Figure 1. In this embodiment, the power transmission 241160W001

[0145] - 27 - element 130 shall have a one-piece clamping ring. The clamping ring may be made of copper or another metallic material. The clamping ring may be designed to be pressed flat against the pipe element 112 when the nut 124 is tightened.

[0146] Figure 4 shows another embodiment of the pipe connection 110. For the description of Figure 4, reference can largely be made to Figure 1. The following discussion focuses only on the differences from Figure 1. In this embodiment, the force transmission element 130 can be made of an oxide ceramic fiber composite material, and in particular may have at least one OCMC ring, also referred to as an OCMC stop. The OCMC ring can be designed with a sufficiently large diameter for the pipe element 112.

[0147] Figure 5 shows a section of Figure 1 in the assembled state. Nut 124 can be one thread deeper in the fitting (the external thread 128). The pipe element 112 can, in particular, be a hybrid pipe, which, for example, is a monolithic ceramic pipe wrapped with OCMC at least at the ends, in the area of ​​the connection. The pipe element 112 can therefore have an OCMC sheath and an inner ceramic pipe, also referred to as an inner layer, in the areas used for the connection, for example, made of a brittle ceramic. Deformation or similar damage to this inner layer would destroy the component.

[0148] The present invention proposes a connection, in particular a gas-tight, pressure- and temperature-resistant connection, without deformation or similar damage to the inner ceramic tube. The front clamping ring (130, 132) and the rear cutting ring (130, 134) can, when the nut is tightened with a predefined rotational and / or tightening torque and / or angle, work their way into the outer OCMC layer of the tube element 112, but not into the inner layer. The inner layer remains unaffected and is not deformed or otherwise damaged. This prevents the component from being directly destroyed. This differs from connections of metal pipes with fittings. Figure 5 shows that the cutting rings penetrate the OCMC layer and thereby create a stop, but the inner layer remains unaffected. 241160W001

[0149] - 28 -

[0150] List of reference signs

[0151] 110 pipe connection

[0152] 112 Pipe element

[0153] 114 further element

[0154] 116 pipe wrenches

[0155] 118 Screw bodies

[0156] 120 strokes

[0157] 122 Sealing element

[0158] 124 Mother

[0159] 126 internal threads

[0160] 128 external threads

[0161] 130 Power transmission element

[0162] 132 front clamping ring

[0163] 134 rear cutting ring

[0164] 136 attacks

Claims

241160W001 - 29 - Claims 1. Pipe connection (110) for end-face, force-fit connection of at least one pipe element (112) and at least one further element (114), wherein the pipe element (112) is at least partially made of at least one oxide ceramic fiber composite material, wherein the pipe connection (110) has at least one pipe screw (116), wherein the pipe screw (116) has a screw body (118) which is configured to receive the pipe element (112) on a first side to a predefined depth and to receive the further element (114) on a second side to a predefined depth, wherein at least one sealing element (122) is arranged between an end face and / or a lateral surface of the pipe element (112) and the screw body (118), wherein the pipe screw (116) has at least one nut (124),wherein one element of the screw body (118) or nut (124) has an external thread and the other element of the screw body (118) or nut (124) has an internal thread, wherein the pipe screw fitting (116) has at least one force transmission element (130), wherein the force transmission element (130) is arranged between the pipe element (112), the screw body (118) and the nut (124) and is configured to transmit axial force to the pipe element (112) when the nut (124) is tightened.

2. Pipe connection (110) according to the preceding claim, wherein the force transmission element (130) comprises at least one element selected from the group consisting of: at least one clamping ring; at least one cutting ring; at least one stop.

3. Pipe connection (110) according to the preceding claim, wherein the force transmission element (130) is at least one clamping and / or cutting ring, wherein the clamping and / or cutting ring is made of at least one metallic material selected from the group consisting of: copper, stainless steel 316, carbon steel, brass, aluminum, Monel, Hastelloy C®, Incolloy, titanium, 6Mo, Alloy 617, Alloy 625, Alloy 400, Alloy C-276, Alloy 600, Alloy 825, Alloy C-22, Alloy 690, Alloy 718, Alloy X-750, Waspalloy, Rene 41, the following materials listed in DIN EN 10095:1999 “Heat-resistant steels and nickel alloys” 1.4713, 1.4724, 1.4742, 1.4762, 1.4749, 1.4737, 1.4878, 1.4828, 1.4835, 1.4833, 1.4845, 1.4841, 1.4864, 1.4876, 1.4877, 1.4872, 1.4818, 1.4854, 1.4886, 1.4887, 1.4821, 1.4512, 1.4510, 1.4509, 1.4301, 1.4948, 1.4541, 1.4941, 1.4950, 1.4951, 1.4362, the following materials are listed in DIN EN 10028-2:2017 "Flat products made from 241160W001 - 30 - Pressure vessel steels - Part 2: Unalloyed and alloyed steels with specified properties at elevated temperatures” 1.0345, 1.0425, 1.0481, 1.0473, 1.5415, 1.5414, 1.6311, 1.6368, 1.7335, 1.7336, 1.7380, 1.7375, 1.7362, 1.7703, 1.7767, 1.4903, stainless steel 304, nylon, PFA and PTFE.

4. Raw connection (110) according to one of the two preceding claims, wherein the force transmission element (130) has two clamping rings (132, 134).

5. Pipe connection (110) according to claim 2, wherein the force transmission element (130) has at least one stop (136) which is made of an oxide ceramic fiber composite material.

6. Pipe connection (110) according to one of the preceding claims, wherein the oxide ceramic fiber composite material of the pipe element (112) and / or the stop (136) comprises at least one oxide ceramic matrix, wherein the oxide ceramic matrix is ​​selected from the group consisting of Si x M y Oz , Si x M1 y M2 w O z , Si x B y N z C w , AIN, M x O y and mixed oxides of the form (M1 x O y / M2 w O z ), wherein the oxide ceramic fiber composite material has a fiber framework of ceramic fibers, wherein the ceramic fibers comprise at least one material selected from the group consisting of: mullite, Al2O3, a combination of mullite and Al2O3.

7. Pipe connection (110) according to one of the preceding claims, wherein the pipe element (112) is a composite pipe, wherein the composite pipe is at least partially made of monolithic ceramic, wherein the composite pipe has an oxide ceramic fiber composite material at least at one end of the composite pipe to be joined.

8. Pipe connection (110) according to one of the preceding claims, wherein the further element (114) comprises at least one element selected from the group consisting of: a composite pipe which is at least partially made of monolithic ceramic and has an oxide ceramic fiber composite material at least at one end of the composite pipe to be joined; a metallic pipe, a plastic element, in particular a hose; a glass element; an apparatus.

9. Pipe connection (110) according to one of the preceding claims, wherein the further element (110) is connected to the pipe screw fitting (116) by at least one weld-in or screw-in fitting. 241160W001 - 31 - 10. Pipe connection (110) according to one of the preceding claims, wherein the pipe element (112) has a pipe diameter of 1 mm to 200 mm, preferably e mm to 51 mm.

11. Pipe connection (110) according to one of the preceding claims, wherein the pipe screw (116), in particular the screw body (118), is a straight pipe screw, a cross, an angle, or a tee.

12. Pipe connection (110) according to one of the preceding claims, wherein the pipe connection (110) is gas-tight and pressure-resistant at temperatures from -200°C to 600°C, preferably -40°C to 200°C.

13. Pipe connection (110) according to one of the preceding claims, wherein the pipe connection (110) is configured to connect the pipe element (112) and the further element (114) in a fluid-conducting and / or gas-tight and technically tight manner.

14. Pipe connection (110) according to one of the preceding claims, wherein the sealing element (122) comprises at least one element from the group consisting of: a flat gasket, a stuffing box gasket, a lens gasket, an O-ring end gasket, a metal gasket.

15. Pipe connection (110) according to one of the preceding claims, wherein the pipe connection (110) comprises the at least one pipe element, the at least one further element and the at least one pipe screw (116).

16. Method for producing a connection between a pipe element (112), at least partially made of at least one oxide ceramic fiber composite material, and a further element (114) using at least one pipe connection (110) according to one of the preceding claims, comprising the steps i. providing the pipe element (112) and the further element (114) and positioning the pipe element (112) and the further element (114) relative to the pipe fitting (116); ii. pre-assembling by force-fit connection of the pipe element (112) and the force transmission element (130) by tightening the nut (124); iii. inserting the sealing element (122) into the pipe fitting (116); 241160W001 - 32 - iv. Force-fit connection of the pipe element (112) and the pipe screw (116) by tightening the nut (124); v. Connection of the pipe screw (116) to the further element (114).

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