Flange connectors for connecting two double-pipe sections, gas supply system and large engine

Abstract

To provide a flange connection portion for connecting two double pipe parts of a gas supply system.SOLUTION: A flange connection portion includes: two first flanges respectively connectable to one of inner walls 1051, 1301 of one of two pipe parts 105, 130; and a fluid channel 4 extended in an axial direction A through two first flanges, and disposed on a center for first fluid, each of the first flanges includes an axial end surface, two axial end surfaces are kept into contact with each other, at least first fastening element 5 is disposed so that two first flanges can be fixed to each other, two second flanges 3 respectively connectable to one of outer walls 1052, 1302 of two pipe parts are disposed, two second flanges 3 define a boundary of a flow connection portion 7 for a second fluid, and the second fluid can flow through a flange connection portion 1 separated from the first fluid through the flow connection portion 7.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a flange connection for connecting two double pipe parts, a gas supply system for a large engine, and a large engine, as described in the preambles of the independent patent claims of each category.

Background Art

[0002] Large engines have long been operated with heavy oil as large diesel engines. Large engines can be designed as two-stroke or four-stroke engines, for example, as longitudinally scavenged two-stroke large diesel engines, and are often used as marine propulsion units or in stationary operation to drive, for example, large generators for generating electrical energy. Since engines usually operate in continuous operation for a considerable period of time, high requirements are placed on operating safety and availability. As a result, in particular, long maintenance intervals, low wear, and economical handling of operating materials are important criteria for the operator. Large diesel engines typically have cylinders with an inner diameter (bore) of at least 200 mm. Recently, large engines with a bore of up to 960 mm or more have been used.

[0003] In terms of economic and efficient operation, compliance with emission limits, and availability of resources, alternatives to heavy oil are currently also being sought for large engines. In this regard, both liquid fuels, i.e., fuels introduced into the combustion chamber in a liquid state, and gas fuels, i.e., fuels introduced into the combustion chamber in a gaseous state, are being used.

[0004] Known examples of liquid fuels as alternatives to heavy fuel oil include other heavy hydrocarbons, alcohols, particularly methanol or ethanol, which remain after petroleum refining, gasoline, diesel fuel, or emulsions or suspensions. For example, emulsions known as multiphase superfine atomized residues (MSARs) are known to be used as fuel. A well-known suspension is a suspension of coal dust and water, which is also used as fuel in large engines. As for gaseous fuels, natural gas such as liquefied natural gas (LNG) is known.

[0005] In particular, large engines capable of operating on at least two different fuels are known, allowing the engine to run on either one fuel or the other depending on the operating conditions or environment.

[0006] Large engines capable of running on at least two different liquid or gaseous fuels are often operated in different operating modes depending on the fuel being used at the time. In the operating mode often called diesel operation, fuel combustion generally occurs according to the principles of compression ignition or autoignition of the fuel. In the mode often called Otto operation, combustion occurs by spark ignition of a flammable, pre-mixed fuel mixture. This spark ignition can occur, for example, by an electric spark from a spark plug, or by the autoignition of a small amount of injected fuel, which then triggers spark ignition of another fuel. The small amount of fuel intended for autoignition is often injected into a pre-chamber connected to the combustion chamber.

[0007] Furthermore, hybrid configurations combining Otto and diesel operation are also known.

[0008] One example of a large engine capable of operating on two different fuels is a large diesel engine designed as a dual-fuel large diesel engine, which is scavenged longitudinally. This large diesel engine can operate in both a liquid mode, where liquid fuel is introduced into the cylinders for combustion, and a gas mode, where gas is introduced into the cylinders as fuel.

[0009] Within the framework of this application, the term “large diesel engine” refers to an engine capable of being operated at least in diesel mode. Therefore, the term “large diesel engine” in particular also includes dual-fuel or multi-fuel large engines capable of being operated in addition to diesel mode, such as Otto mode.

[0010] Of course, large engines can also be designed as gas engines that can operate using only one or more types of gas as fuel.

[0011] To operate on gas as fuel, a large engine must have a gas supply system capable of supplying the gas to be used as fuel to the cylinders. Typically, the gas supply system comprises at least a gas delivery system for introducing gas into the cylinders and a pressure regulation system, the pressure regulation system setting the gas pressure to the desired pressure for introduction into the cylinders and supplying it to the gas delivery system. Such a pressure regulation system is also called an integrated gas pressure regulation (iGPR). In addition to the pressure control valve, the iGPR typically comprises other components such as a flow meter, various sensor boxes, shut-off valves and filter devices.

[0012] For safety reasons, double-walled gas pipes are used in such gas supply systems. Such pipes or pipe sections comprise an inner channel through which gas flows and an annular outer channel designed coaxially with the inner channel. A second fluid (e.g., air) flows in the outer channel as a protective medium. Typically, the second fluid in the outer channel is guided in a countercurrent to the first fluid in the inner channel, in this case gas. In addition, the double-walled pipe is operated such that the pressure in the outer channel is lower than that in the inner channel. In a gas transport pipe system, if, for example, a leak occurs in the inner channel, the gas escapes from the inner channel into the outer channel, where it is carried away by the protective medium against the direction of gas flow in the inner channel. To ensure that this protective function is always guaranteed, it must be ensured that the inner system transporting the gas is always surrounded by the outer system transporting the protective medium.

[0013] The various components of the iGPR are also connected to each other via double-walled sections. For this purpose, it is necessary that all components through which the fuel gas flows, and the tubing sections connecting those components, be connected with high operational safety so that the protective medium prevents the gas from escaping into the environment.

[0014] For this purpose, for example, Danish Patent Application No. 201770407A1 proposes a flanged connection to which two double-walled pipe sections can be connected together. This flanged connection comprises a central axial bore for gas and several non-central channels through which a protective medium can be separated from the gas and flow through the flanged connection. The two flanges at the ends of the pipe sections to be connected are pressed together in a manner known to itself by several threaded connections. If these threaded connections fail, both the gas-transporting central bore for the gas and the non-central channels for the protective medium will separate from each other or at least leak, thus potentially allowing the gas to escape into the environment. This poses a considerable safety risk. [Prior art documents] [Patent Documents]

[0015] [Patent Document 1] Danish Patent Application No. 201770407A1 [Overview of the project] [Problems that the invention aims to solve]

[0016] Based on this cutting-edge technology, therefore, an object of the present invention is to propose a flange connection for connecting two double-pipe sections of a gas supply system, which ensures increased operational safety. Furthermore, an object of the present invention is to propose a gas supply system for a large engine including such a flange connection. Another object of the present invention is to propose a large engine having such a gas supply system. [Means for solving the problem]

[0017] The subject matter of the present invention, which satisfies these objectives, is characterized by the features of the independent claims in each category.

[0018] Accordingly, according to the present invention, a flange connection is proposed for connecting two double-pipe sections of a gas supply system, the flange connection comprising two first flanges, each which can be connected to the inner wall of one of the two pipe sections, and a centrally located fluid channel for a first fluid, extending axially through the two first flanges, each first flange having an axial end face, the two axial end faces abutting each other, and provided with at least one first fastening element, the two first flanges being fastened to each other, and provided with two second flanges, each which can be connected to the outer wall of one of the two pipe sections, the two second flanges defining a boundary of a flow connection for a second fluid, through the flow connection, the second fluid being able to flow through the flange connection separated from the first fluid, and provided with at least a second fastening element, the two second flanges being fastened to each other, the second fastening element being different from the first fastening element.

[0019] Therefore, according to the present invention, a flange connection is proposed comprising two first flanges and two second flanges, the two first flanges comprising a fluid channel for a first medium, and the two second flanges defining a boundary of a flow connection for a second fluid so that the second fluid can flow through a flange connection separated from the first fluid. Since the first fastening elements that secure the two first flanges together are different from the second fastening elements that secure the two second flanges together, even if the first fastening elements fail or cause leakage, leakage of the first fluid, such as a gas used as fuel, into the environment is reliably prevented by the second fastening elements, resulting in a significant increase in operational safety.

[0020] For practical reasons, it is preferable to provide a plurality of first fastening elements or a plurality of second fastening elements, and the first fastening elements or second fastening elements are designed as screw connections.

[0021] In a preferred embodiment, the two second flanges are designed and arranged such that they overlap axially. A sealing element is preferably provided between the two second flanges in the region where they overlap.

[0022] This radial arrangement of the sealing element allows relative motion between the two second flanges to be absorbed without compromising the sealing function.

[0023] In a first preferred embodiment, the two second flanges form a first fastening element, with the second flange surrounding the respective radially outer portions of the two first flanges, such that the two radially outer portions of the first flange are designed and arranged to be disposed axially between the two second flanges. This means that in this embodiment, the two second flanges are used to press the two first flanges against each other.

[0024] When a plurality of second fastening elements are provided, it is particularly preferred that the second fastening element includes a screw connection and a bayonet connection that ensures the fixation of the two second flanges. In case the screw connection of the second fastening element fails, the bayonet connection ensures that the second flanges remain fixed to each other, and thus the first fastening element also continues to function fully.

[0025] In a second preferred embodiment, the two second flanges are arranged spaced apart from each other axially, the two first flanges are arranged axially between the two second flanges, and a substantially cylindrical sleeve is provided that surrounds the two first flanges and the two second flanges radially outward. The sleeve functions to close the annular space between the two second flanges radially such that a second fluid can flow through the sleeve from one second flange to the other second flange.

[0026] Providing a plurality of fixing elements to fix the sleeve to the two second flanges is a preferred means.

[0027] Preferably, a sealing element is provided between each second flange and the sleeve in any case, so that the second fluid, or in case of an accident, a mixture of the second fluid and the first fluid, cannot flow out of the sleeve into the environment. Preferably, the sealing element is designed as an O-ring inserted into the circumferential groove of each second flange.

[0028] A more preferable embodiment is one in which each first flange has a collar that forms the axial end face of the first flange, and the first fastening element is designed as a fastening device including two fastening elements, each having a groove that extends circumferentially on the first flange and is designed to receive two collars, and is provided with a plurality of tensioning elements that can tighten the fastening elements against each other. Thus, in this embodiment, the two first flanges are pressed against each other by the fastening device.

[0029] The two collars are advantageously designed so that when joined together, they form a trapezoidal contour in the circumferential direction, tapering radially outward. This design allows the axial end faces of the first flange to press against each other in a particularly efficient manner.

[0030] For practical reasons, it is preferable that each tension element includes a screw that extends perpendicular to the axial direction in all cases.

[0031] A more advantageous approach is for the fixing element to include multiple screws, each longer axially than the sleeve surrounding the second flange.

[0032] Furthermore, the present invention proposes a gas supply system for a large engine, which can supply gas as fuel to at least one cylinder of a large engine, comprising a first double-tube section and a second double-tube section, each section comprising an inner channel for gas fuel and an outer channel for a second fluid arranged around the inner channel, and the two double-tube sections are connected by a flange connection section designed in accordance with the present invention.

[0033] Furthermore, the present invention proposes a large engine having at least one cylinder, in which a gas supply system is provided that can supply gas as fuel to each cylinder, and the gas supply system is designed in accordance with the present invention.

[0034] In a preferred embodiment, the large engine is designed as a longitudinally scavenged two-stroke large diesel engine, and is preferably designed as a dual-fuel large diesel engine that can be operated in liquid mode, in which liquid fuel is introduced into the cylinders for combustion, and also in gas mode, in which gas is introduced into the cylinders as fuel.

[0035] Further advantageous means and embodiments of the present invention are provided by the dependent claims.

[0036] The present invention will be described in more detail below with reference to examples and drawings. The drawings are as follows. [Brief explanation of the drawing]

[0037] [Figure 1] This is a plan view of the first embodiment of the flange connection portion according to the present invention in the axial direction. [Figure 2] A cross-sectional view of the embodiment in Figure 1, in a cross-section along the cross-sectional line II-II in Figure 1. [Figure 3] A cross-sectional view of the embodiment in Figure 1, in a section along the cross-sectional line III-III in Figure 1. [Figure 4] A diagram of a second embodiment of the flange connection portion according to the present invention. [Figure 5] A diagram of a second embodiment in which the sleeve and fixing elements have been removed. [Figure 6] A cross-sectional view of the second embodiment in a section along the radial direction. [Figure 7] A cross-sectional view of the second embodiment in a section along the cross-sectional line VII-VII in Figure 6. [Figure 8] A diagram of a third embodiment of the flange connection part according to the present invention. [Figure 9] A diagram of a third embodiment in which the sleeve and fixing elements have been removed. [Figure 10] A cross-sectional view of the third embodiment in a cross-section along the axial direction. [Figure 11] A schematic diagram of an embodiment of the gas supply system according to the present invention in a large engine. [Modes for carrying out the invention]

[0038] The term "large engine" typically refers to an engine used as the primary propulsion system for a ship, or in stationary operation, for example, to drive a large generator for generating electrical energy. Typically, the cylinders of a large diesel engine each have an internal bore of at least about 200 mm. The term "longitudinally scavenged" means that scavenging or intake air is introduced into the cylinder in the lower end region.

[0039] In the following description of the present invention relating to embodiments, in an exemplary sense, we refer to the case of a dual-fuel heavy diesel engine, i.e., a particularly practical heavy engine designed as an engine capable of operating on two different fuels. In particular, embodiments of this heavy diesel engine can be operated in liquid mode, in which only liquid fuel is injected into the combustion chamber of the cylinder. Typically, the liquid fuel, such as heavy oil or diesel oil, is injected directly into the combustion chamber in a timely manner and ignited there according to the diesel principle of autoignition. The heavy diesel engine can also be operated in gas mode, in which the gas acting as fuel, such as natural gas, is ignited in the combustion chamber in the form of a pre-mixed mixture. In gas mode, the operation of the heavy diesel engine is carried out particularly by the low-pressure method. That is, the gas is introduced into the cylinder in a gaseous state, and the gas injection pressure is a maximum of 5 MPa (50 bar), preferably a maximum of 2 MPa (20 bar). The air-gas mixture is spark-ignited in the combustion chamber according to Otto's principle. This spark ignition is typically achieved by introducing a small amount of self-igniting liquid fuel (e.g., diesel oil or heavy oil) into the combustion chamber or sub-combustion chamber at an appropriate moment, allowing it to self-ignite in the combustion chamber, and then causing spark ignition of the fuel-air mixture.

[0040] In gas mode, large engines require gas, such as natural gas, as fuel. For this purpose, a gas supply system is required. Figure 11 schematically shows an embodiment of a gas supply system according to the present invention in a large engine. The large engine as a whole is denoted by reference numeral 200, and the gas supply system as a whole is denoted by reference numeral 150. The gas supply system 150 comprises a gas delivery system 100 for introducing gas into the cylinder and a pressure regulating system 130, the pressure regulating system 130 which sets the gas pressure to a desired pressure for introduction into the cylinder and provides it to the gas delivery system. Such a pressure regulating system 130 is also called an engine-mounted pressure regulating valve (iGPR). In addition to the pressure regulating valve, the iGPR typically comprises other components such as a flow meter, various sensor boxes, shut-off valves, and a filtering device.

[0041] The embodiments described herein refer to a large engine designed as a dual-fuel, two-stroke, large diesel engine with longitudinal scavenging.

[0042] A large diesel engine 200 has at least one, but usually more, cylinders 210. Figure 11 shows a total of four cylinders 210. Inside each cylinder, a piston (not shown) is positioned in a manner known to itself so as to be able to move back and forth along the cylinder axis between top dead center and bottom dead center. The piston is connected to a crosshead (not shown) by a piston rod (not shown) in a manner known to itself, and the crosshead is connected to a crankshaft (not shown) via a push rod (not shown), so the motion of the piston is transmitted to the crankshaft via the piston rod, crosshead and push rod to rotate the crankshaft. The upper side of the piston, together with the cylinder cover (not shown), defines the boundary of the combustion chamber into which fuel is introduced for combustion. In gas mode, this fuel is a gas, such as natural gas, for example, liquefied natural gas (LNG). In the low-pressure process, for example, gas is introduced into each cylinder 210, preferably substantially midway between the top dead center and bottom dead center of the piston, through the cylindrical wall of the cylinder 210 or through the cylinder liner. In the cylinder 210, the gas mixes with the scavenging gas during the compression motion of the piston, thereby forming a flammable mixture, which is then spark-ignited when the piston is substantially at top dead center. Spark ignition is preferably performed by injecting a self-igniting fuel, such as heavy oil or diesel fuel, into the sub-combustion chamber of each cylinder.

[0043] As shown in Figure 11, each cylinder 210 is provided with two gas supply pipes 104, each of which leads to a gas inlet nozzle (not explicitly shown) of the cylinder 210 or cylinder liner. The two gas inlet nozzles of each cylinder 210 are preferably opposite each other. The gas supply pipes 104 branch off from a second pipe 102 or a third pipe 103, which are designed as main pipes for supplying gas to the cylinders 210. From the upper pipe, i.e., the third pipe 103, one of the gas supply pipes 104 branches off to each cylinder 210 in both cases, and from the lower pipe, i.e., the second pipe 102, one of the gas supply pipes 104 also branches off to each cylinder 210 in both cases. Shut-off valves 110 are provided at both ends of the second pipe 102 and at both ends of the third pipe 103. Each shut-off valve 110 has a closed position and an open position. When the shut-off valve 110 is in the open position, gas, or more generally the first fluid, can flow through the shut-off valve 110. When the shut-off valve 110 is in the closed position, the passage through the shut-off valve 110 is blocked to the gas or the first fluid.

[0044] As shown in the figure, to the right of the two shut-off valves 110 located at the right ends of the second pipe 102 and the third pipe 103, a first pipe 101 is provided connecting these two shut-off valves 110 to each other. The first pipe 101 is provided with a gas inlet 105, through which gas from the pressure regulating system 130 can be supplied to the first pipe 101. The pressure regulating system 130, although not shown in detail, is equipped with at least one pressure regulating valve in a manner known to itself. Furthermore, the pressure regulating system 130 may be equipped with one or more filters, flow meters, various sensors, an aeration valve or a venting valve, and shut-off valves. The gas is supplied to the pressure regulating system 130 from a storage tank (not shown) for gas used as fuel.

[0045] All gas transport pipes, i.e., each of the gas supply pipes 104 in particular, the first pipe 101, the second pipe 102, the third pipe 103, and all pipes or pipe sections connecting the components of the pressure regulating system 130 (not shown in detail), as well as the connection between the pressure regulating system 130 and the gas inlet 105, are designed as double pipes or double pipe sections, each having an inner channel 106 through which the gas used as fuel flows, and an outer channel 107 for a second fluid that functions as a protective medium. This second fluid is, for example, air. The outer channel 107 is designed, for example, as an annular channel and is coaxial with the inner channel.

[0046] As shown in the figure, a flushing pipe 108 is provided to the left of two shut-off valves 110 located at the left ends of the second pipe 102 and the third pipe 103, and to the left of these two shut-off valves 110 is provided. The flushing pipe 108 is provided with an outlet 109, through which fluid can be discharged from the flushing pipe 108. The flushing pipe 108 is not required for normal gas operation of the large engine 200. That is, as shown in the figure, the two shut-off valves 110 on the left are in the closed position during normal operation. For cleaning or maintenance work, these two shut-off valves 110 can be opened to guide fluid, such as a cleaning agent, through the inner channel 106 and discharge through the flushing pipe 108 and outlet 109. Since the flushing pipe 108 is not required for normal gas operation, it is preferably designed as a simple single pipe.

[0047] During operation of the large engine 200 in gas mode, the two shut-off valves 110 on the left side of the diagram are closed, and the two shut-off valves 110 on the right side of the diagram are open. The gas used as fuel is then introduced by the pressure regulating system 130 through the gas inlet 105 into the inner channel 106 of the first pipe 101, and from there it flows through the inner channels 106 of the second pipe 102 and the third pipe 103, as well as the inner channel 106 of the gas supply pipe 104, as shown by the arrow labeled reference numeral G in Figure 11, to the gas inlet nozzle in the cylinder 210.

[0048] Simultaneously, a second fluid is guided through the outer channel 107 of the gas supply pipe 104, the second pipe 102, the third pipe 103, and the first pipe 101, acting as a protective medium to prevent gas from escaping into the environment in the event of leakage. Preferably, the protective medium is guided countercurrently through the outer channel 107, as indicated by the arrow labeled reference numeral F in Figure 11. This means that the protective medium flows in the opposite direction to the gas. Furthermore, the pressure of the protective medium in the outer channel 107 is adjusted so that its pressure is lower than the pressure of the gas in the inner channel 106. The second fluid acting as the protective medium is preferably air.

[0049] The various double pipes and pipe sections connecting the components of the pressure regulating system 130 must be connected via flanged connections designed to be as safe as possible. In Figure 11, only one of these flanged connections is shown in an exemplary sense, and the whole is indicated by reference numeral 1. Figure 11 shows flanged connection 1 connecting the pressure regulating system 130 to the gas inlet 105.

[0050] Accordingly, in the following description of preferred embodiments of the flange connection 1 according to the present invention, the flange connection 1 connecting the gas inlet 105 to the pressure regulating system 130 is referred to in an exemplary sense in all cases. Of course, the flange connection 1 can also be provided at any other location where both double-pipe sections need to be connected, in other words, it can be provided particularly between components of the pressure regulating system 130, i.e., iGPR.

[0051] In the following, a first embodiment of the flange connection portion 1 according to the present invention will be described based on Figures 1 to 3. Figure 1 shows a plan view of the first embodiment of the flange connection portion 1 according to the present invention in the axial direction A, where the axial direction A corresponds to the direction in which the first fluid, in this case the gas functioning as fuel, flows through the flange connection portion 1. This means that Figure 1 shows a plan view of the flange connection portion 1 as seen in the axial direction A. Figure 2 shows a cross-sectional view of the flange connection portion 1 in a cross-section along the cross-sectional line II-II in Figure 1. Figure 3 shows a cross-sectional view of the flange connection portion 1 in a cross-section along the cross-sectional line III-III in Figure 1.

[0052] In the following, the direction perpendicular to the axial direction A will be referred to as the radial direction.

[0053] The flange connection 1 for connecting the two double-pipe sections, the gas inlet 105 and the pressure regulating system 130, includes two first flanges 2, each of which is connected to the inner wall 1051 or 1301 of one of the two pipe sections 105 and 130. That is, one of the first flanges 2 is connected to the inner wall 1051 of the gas inlet 105, and the other first flange 2 is connected to the inner wall 1301 of the pressure regulating system 130. Each first flange 2 is preferably irremovably connected to the respective inner wall 1051 or 1301, for example, by welding.

[0054] The flange connection 1 further has a centrally located fluid channel 4 extending axially A through two first flanges 2, the fluid channel 4 connecting two inner channels 106 to each other so that a gas used as fuel can flow from the inner channel 106 of the gas inlet 105 through the fluid channel 4 of the flange connection 1 into the inner channel 106 of the pressure regulating system 130.

[0055] Each first flange 2 has an axial end face 21, and the first flanges 2 are arranged such that the two axial end faces 21 abut each other. To prevent gas from escaping through the fluid channel 4 between the two end faces 21, a sealing element 22, preferably an O-ring 22, is provided on at least one of these end faces 21. Furthermore, at least a first fastening element 5 is provided that can fix the two first flanges 2 to each other, so that the two axial end faces 21 are pressed against each other. The first fastening element 5 will be described in more detail later.

[0056] The flange connection section 1 further includes two second flanges 3, each of which is connected to the outer wall 1052 or 1302 of one of the two pipe sections 102, 130. That is, one of the second flanges 3 is connected to the outer wall 1052 of the gas inlet 105, and the other second flange 3 is connected to the outer wall 1302 of the pressure regulating system 130. Each second flange 3 is preferably irremovably connected to the respective outer wall 1052 or 1302, for example, by welding.

[0057] Each second flange 3 has an axial end face 31, and the second flanges 3 are arranged such that the two axial end faces 31 abut each other. Furthermore, at least a second fastening element 6 is provided that can fix the two second flanges 3 to each other. In the first embodiment, the two axial end faces 31 of the second flanges 3 are pressed against each other by the second fastening element 6.

[0058] Furthermore, the two second flanges 3 define the boundary of the flow connection 7 for the second fluid, i.e., a protective medium, so that the second fluid can flow from the outer channel 107 of the gas inlet 105 through the flow connection 7 between the two first flanges 2 and the two second flanges 3 into the outer channel 107 of the pressure regulating system 130. The second fluid flows through the flange connection 1, which is separated from the first fluid that flows through the centrally located fluid channel 4.

[0059] In the first embodiment, the two second flanges 3 function as a first fastening element 5, the axial end faces 21 of the two first flanges 2 are pressed against each other by them.

[0060] To this end, the two second flanges 3 form a circumferentially extending annular groove when assembled, and each second flange 3 has an annular projection 33 radially positioned on the inside of each second flange 3 so that the two first flanges 2 are received within this annular groove. This means that each of the two first flanges 2 has an annular radially outer portion 23, which is surrounded by the two projections 33 of the second flange 3. Thus, when assembled, the two radially outer portions 23 of the first flange 2 are positioned between the two projections 33 of the second flange 3 with respect to the axial direction A.

[0061] With the assistance of the second fastening means 6, when the two second flanges 3 are tightened against each other, the axial end faces 21 of the two first flanges are also pressed against each other in a sealed manner. In this way, the two second flanges 3 function as a first fastening element 5, through which the two first flanges 2 are pressed against each other.

[0062] It has been found to be advantageous to design and position the two second flanges 3 in such a way that they overlap with respect to the axial direction A. For this purpose, as shown in the figures (Figures 2 and 3), the right-hand second flange 3 has an annular extension 34 radially inward with respect to its axial end face 31, on which the left-hand second flange 3 rests, as shown in the figures. Thus, the annular extension 34 and the left-hand second flange 3, as shown in the figures, form an overlapping region 35 where the two second flanges 3 overlap when viewed in the axial direction A. Preferably, a sealing element 36, preferably an O-ring 36, is placed in this overlapping region 35 to improve the seal between the two second flanges 3.

[0063] The second fastening element 6, which can secure the two second flanges 3 to each other, includes a plurality of threaded connectors 61 and, in addition, a bayonet connector 62 that ensures the two second flanges 3 are secured to each other.

[0064] In particular, as can be seen in Figures 1 and 2, the threaded connections 61, in this case six threaded connections, are arranged on an annular line around the fluid channel 4. Each threaded connection 61 is in any case equipped with a threaded bolt or screw 611 and a nut 612. Each screw 611 extends axially A through both second flanges 3, so that by tightening the nuts 612, the two second flanges 3 are fixed to each other and their end faces are pressed against each other.

[0065] In particular, as seen in Figures 1 and 3, the bayonet connection 62 comprises several bolts 622, which are fixed within the bore of one of the two second flanges 3, which in Figure 3 is the left second flange 3. A total of six bolts 622 are provided, each positioned between two of the threaded connection 61. Each bolt 622 extends axially A and has a countersunk head 623 at its free end. In the other of the two flanges 3, which in Figure 3 is the right second flange 3, each bolt 622 is provided with an elongated hole 624, which (when viewed circumferentially) is larger in diameter at one end than the diameter of the countersunk head 623 of the bolt 622 and smaller in diameter at the other end than the diameter of the countersunk head 623 of the bolt 622. Each bolt 622 is sized such that, in the axial direction A, each bolt 622 can engage through the elongated hole 624 assigned to it.

[0066] To assemble, the two second flanges 3 are first inserted into each other in the usual manner for the bayonet connector 62, so that each countersunk head 623 engages through the end of the larger diameter slotted hole 624 assigned to it. Subsequently, the two second flanges 3 are rotated relative to each other around the axial direction A, so that the bolts 622 with countersunk heads 623 now abut against the end of the smaller diameter slotted hole 624, thereby locking the bayonet connector 62.

[0067] Therefore, two independent connectors are provided to protect the flange connector 1 from leakage or opening of the flange connection. The two second flanges 3 that press the two first flanges 2 against each other function as a first fastening element 5 for securing the two first flanges 2. In the event of a malfunction or damage to the threaded connector 61 that tightens the two second flanges 3 against each other as part of the second fastening element 6, the bayonet connector 62 ensures that the connection between the two second flanges 3 does not open and remains tight. Thus, it is also guaranteed that a sealed connection between the two first flanges is maintained. This means that the operational safety of the flange connector 1 is considerably increased.

[0068] In the following, a second embodiment of the flange connection portion 1 according to the present invention will be described, this time with reference to Figures 4 to 7. Only the differences from the first embodiment will be described in more detail. For other points, the description of the first embodiment applies to the second embodiment in the same or similar manner. In the second embodiment, identical or functionally equivalent parts are represented by the same reference numerals as described in relation to the first embodiment.

[0069] Figure 4 shows an embodiment of the flange connection 1 according to the present invention. Figure 5 shows a second embodiment as in Figure 4, but with the sleeve and fixing elements removed for better understanding. Figure 6 shows a cross-sectional view of the second embodiment of the flange connection 1 in a cross-section along axial direction A, and Figure 7 shows a cross-sectional view of the second embodiment in a cross-section along cross-sectional line VII-VII in Figure 6.

[0070] In a second embodiment of the flange connection according to the present invention, the two second flanges 3 are spaced apart from each other with respect to the axial direction A (see Figures 5 and 6 in particular). The two first flanges 2 are positioned between the two second flanges 3 with respect to the axial direction A. Furthermore, a substantially cylindrical sleeve 8 is provided that radially surrounds the two first flanges 2 and the two second flanges 3. The sleeve 8 is sized such that it rests on the two second flanges 3 and radially closes the space between the two second flanges 3. The inner diameter of the sleeve 8 substantially corresponds to the outer diameter of the two second flanges 3, so that the sleeve 8 can be pressed over the two second flanges 3 in the axial direction A. Preferably, the outer diameters of the two first flanges 2 are smaller than the outer diameters of the two second flanges 3 and therefore smaller than the inner diameter of the sleeve 8. By means of this, the flow connection 7 for the second fluid can be realized in a simple manner.

[0071] Furthermore, several fixing elements 9 are provided to secure the sleeve 8 to the second flange 3. These fixing elements 9 are shown only in Figure 4. In the second embodiment, a total of four fixing elements 9 are provided, i.e., two on each side of the flange connection 1. Each fixing element 9 is designed, for example, as a disc-shaped ring portion extending in a quarter circle. As shown in Figure 6, the sleeve 8 is coplanar with respect to the two second flanges 3 with respect to the axial direction A. To secure the sleeve 8, two of the fixing elements 9 are fastened to each axial end face of the sleeve 8 by screws 91 (Figure 4). With respect to their radial extensions, the fixing elements 9 are sized such that in each case they project radially inward beyond the axial end face of the sleeve 8 and thus contact the outer axial end face of the second flange 3. In this way, the sleeve 8 can be secured to the second flange 3. Preferably, a sealing element, preferably designed as an O-ring, is provided between all the second flanges 3 and the sleeve 8. For this O-ring, for example, a circumferential groove 38 is provided on the radially outer interface of each second flange 3, and the O-ring is inserted into the circumferential groove 38.

[0072] In the second embodiment, the second fastening element thus comprises a sleeve 8 and a fixing element 9.

[0073] In the second embodiment, a plurality of screw connections 51 are provided as the first fastening element 5 and are arranged on an annular line around the central fluid channel 4. In the second embodiment, six screw connections 51 are provided as the first fastening element, in an exemplary sense.

[0074] Each threaded connector 51 comprises a threaded bolt or screw 511 and a nut 512. For each screw 511, an outwardly (radially) open groove 513 is provided in all cases on the radially outer surface of the two first flanges 2, and the groove 513 in all cases extends axially A through both first flanges 2. Each groove 513 has a substantially U-shaped contour. Embodiments having outwardly open grooves 513 have the advantage that the threaded connectors 51 can be inserted into the grooves 513 from the outside and do not need to be passed through a bore. By tightening the nuts 512, the two first flanges 2 are fixed to each other and their end faces 21 are pressed against each other.

[0075] After the first fastening element is attached, the sleeve 8 is pressed over the two second flanges 3 and secured to the second flanges 3 by the fixing element 9.

[0076] Below, a third embodiment of the flange connection portion 1 according to the present invention will be described with reference to Figures 8 to 10. Only the differences from the first and second embodiments will be described in more detail. For other points, the descriptions relating to the first and second embodiments also apply to the third embodiment in the same or similar manner. In the third embodiment, identical or functionally equivalent parts are represented by the same reference numerals as described in relation to the first and second embodiments.

[0077] Figure 8 shows a diagram of a third embodiment of the flange connection 1 according to the present invention. Figure 9 shows a diagram of the third embodiment, but the sleeve and fixing elements have been removed for better understanding. Figure 10 shows a cross-sectional view of the third embodiment in a cross section along the axial direction A.

[0078] In a third embodiment of the flange connection 1 according to the present invention, two second flanges 3 are spaced apart from each other with respect to the axial direction A, and a sleeve 8 is provided that extends axially A from one of the second flanges to the other. Four fixing elements 9 are provided to fix the sleeve 8 to the second flanges 3. A total of four fixing elements 9 are provided, i.e., two on each side of the flange connection 1. Each fixing element 9 is designed, for example, as a disc-shaped ring portion extending on a quarter circle. As shown in Figure 10, each fixing element 9 engages with a circumferential groove 39 provided on the radially outer interface of each second flange 3. A plurality of threaded connections 92 are further provided to fix the sleeve 8, each equipped with a threaded bolt 921 and a nut 922. The fixing elements 9 abut the outer axial end faces of the second flanges 3. Each threaded bolt 921 extends axially A through two of the fixing elements 9 and the sleeve 8. By tightening the nut 922, the two second flanges 3 are secured to each other by the sleeve 8.

[0079] The two inner flanges 2 are tightened together by a clamp connection. For this purpose, each first flange 2 has a collar 25 which in either case forms the axial end face 21 of the first flange 2. The two collars 25 project outward radially beyond the rest of the first flange 2 and abut against each other when assembled.

[0080] The first fastening element 5 is designed as a clamping device and includes two clamping elements 53, each having a groove 54 that extends circumferentially on the first flange 2 and is designed to receive two collars 25. Each clamping element 53 is substantially semi-annular in shape. Multiple tension elements 55, namely four tension elements in this case, are provided to tighten the two clamping elements 53 against each other.

[0081] Each tension element 55 is designed as a screw, and for these screws, one wall of the clamping element 53 is provided with a bore extending perpendicular to the axial direction A. The other wall of the clamping element 53 is provided with a corresponding threaded bore, so that by engaging each screw with the threaded bore and tightening each screw, the two clamping elements 53 are pulled relative to each other, thereby sealing and pressing the two first flanges 2 relative to each other.

[0082] It is particularly preferable that the two collars 25 are designed such that when joined together they form a trapezoidal contour (see Figure 10) when viewed circumferentially, tapering radially outward. Accordingly, the grooves 54 of the two clamping elements 53 are also designed with a trapezoidal contour so that the collars are flat against the walls of the grooves 54.

Claims

1. A flange connection for connecting two double-pipe sections of a gas supply system, wherein the flange connection comprises two first flanges (2), each of which can be connected to the inner wall (1051, 1301) of one of the two pipe sections (105, 130), and a centrally located fluid channel (4) for a first fluid, extending axially (A) through the two first flanges (2), each having an axial end face (21), the two axial end faces (21) abutting against each other, and at least a first fastening element (5) is provided to fasten the two first flanges (2) to each other, wherein the flange connection comprises two second flanges (3), each of which can be connected to the outer wall (1052, 1302) of one of the two pipe sections, and the two second flanges (3) are A flange connection comprising a boundary of a flow connection (7) for two fluids, through which the second fluid can flow through the flow connection (7) through the flange connection (1) separated from the first fluid, and characterized in that at least a second fastening element (6) is provided which the two second flanges can be fastened to each other, the second fastening element (6) being different from the first fastening element (5), the two second flanges (3) forming the first fastening element (5), the second flanges (3) surrounding the respective radially outer portions (23) of the two first flanges, and so designed and positioned such that the two radially outer portions (23) of the first flange (2) are positioned between the two second flanges (3) with respect to the axial direction (A).

2. The flange connection according to claim 1, wherein a plurality of second fastening elements (6) are provided, and the second fastening elements (6) are designed as screw connection portions (61).

3. The flange connection according to claim 1 or 2, wherein the two second flanges (3) are designed and arranged such that they overlap with respect to the axial direction (A).

4. The flange connection according to claim 1, wherein a plurality of second fastening elements are provided, and the second fastening elements include a screw connection portion (61) and a bayonet connection portion (62) that ensures the fixing of the two second flanges (3).

5. A gas supply system for a large engine, wherein the gas supply system is capable of supplying gas as fuel to at least one cylinder (210) of the large engine (200), and the gas supply system comprises a first double-tube section and a second double-tube section, each section comprising an inner channel (106) for gas fuel and an outer channel (107) for a second fluid arranged around the inner channel, wherein the two double-tube sections are connected by a flange connection (1) designed according to any one of claims 1 to 4.

6. A large engine having at least one cylinder (210), wherein a gas supply system (150) capable of supplying gas as fuel to each cylinder (210) is provided, characterized in that the gas supply system (150) is designed according to claim 5.

7. The large-capacity engine according to claim 6, which is designed as a longitudinally scavenging two-stroke large-capacity diesel engine, which can be operated in a liquid mode in which liquid fuel is introduced into the cylinder (210) for combustion, and can also be operated in a gas mode in which gas is introduced into the cylinder (210) as fuel.

8. The large-capacity engine according to claim 7, wherein the large-capacity two-stroke diesel engine that scavenges in the longitudinal direction is a dual-fuel large-capacity diesel engine.

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