Pipe connection device, fuel supply system, internal combustion engine and method of operating internal combustion engine
By employing double-walled connecting pipes and an inert gas system in the fuel supply system, the problems of high fuel leakage risk and limited material selection have been solved, resulting in improved safety and reliability, extended service life of the connecting pipes, and rapid detection and handling of leaks.
Patent Information
- Application Number
- CN202380097948.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-05-08
- Publication Date
- 2025-12-19
AI Technical Summary
Existing fuel supply systems face high leakage risks, limited material selection, and connection problems caused by engine vibration when using alternative fuels, especially the reliability and safety of flexible connections are difficult to guarantee.
The system employs a double-walled connecting pipe and an inert gas system. By filling the leak space with inert gas and maintaining an inert atmosphere in the leak space of the double-walled connecting pipe through the connecting device, inert gas is supplied from one connecting block to another using an inert gas pipe. At the same time, the leak space of the double-walled connecting pipe is kept free of inert gas during normal engine operation, increasing the life of the connecting pipe, and leaking fuel is discharged through the leak channel in case of a leak.
It effectively reduces the fire risk caused by fuel leaks, improves the flexibility of material selection, enhances the reliability and safety of connections, extends the service life of connecting pipes, and enables rapid detection and handling of leaks.
Smart Images
Figure CN121175484A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present invention relates to a pipe connection arrangement for a fuel supply system of an internal combustion engine according to claim 1. The present invention also relates to a fuel supply system, an internal combustion engine and a method of operating an internal combustion engine. BACKGROUND
[0002] There is an increasing need for large internal combustion engines, such as marine and power plant engines, which can be operated using other types of fuel than conventional liquid fuels, such as light fuel oil or heavy fuel oil. The alternative fuel can be a liquid fuel, such as methanol or ammonia, or a gaseous fuel, such as natural gas or hydrogen.
[0003] The use of alternative fuels helps to reduce carbon dioxide and other emissions from the engine. However, the use of alternative fuels also presents a number of challenges. For example, the leakage of gaseous fuels presents a more serious safety risk than the leakage of liquid fuels with a high flash point. Also, some fuels, such as methanol, can be more toxic than conventional fuels, such as light fuel oil.
[0004] In many cases, the use of alternative fuels results in the need for additional safety measures. A common safety measure to address the risk of fire and poisoning is to use double-walled pipes for transporting the fuel. A double-walled pipe comprises an inner pipe for transporting the fuel and an outer pipe arranged coaxially around the inner pipe to form an annular leakage space between the two pipes. The leakage space collects fuel that can leak from the inner pipe and allows the detection of leaks and the transportation of leaked fuel to a safe location, such as a tank or outdoors. In case of a leak, the inner pipe and the leakage space can be purged using an inert gas, such as nitrogen.
[0005] Double-walled pipes of a fuel supply system are typically steel pipes. However, due to vibrations of the engine, all connecting pipes cannot be constructed as rigid pipes, but the fuel supply system needs to comprise flexible sections that allow the engine to move. The requirement of flexibility limits the availability of suitable materials. SUMMARY
[0006] It is an object of the present invention to provide a pipe connection arrangement for a fuel supply system of an internal combustion engine. It is a further object of the present invention to provide an improved fuel supply system for an internal combustion engine, an improved internal combustion engine and a method of operating an internal combustion engine.
[0007] The pipe connection arrangement according to the present invention comprises
[0008] - a first connection block configured to be rigidly attached to the engine, the first connection block comprising a fuel inlet for receiving fuel, a fuel outlet, a fuel passage establishing fluid communication between the fuel inlet and the fuel outlet, an inert gas inlet, an inert gas outlet and an inert gas passage establishing fluid communication between the inert gas inlet and the inert gas outlet,
[0009] - a second connection block configured to be arranged at a distance from the engine, the second connection block comprising a fuel inlet for receiving fuel, a fuel outlet, a fuel passage establishing fluid communication between the fuel inlet and the fuel outlet, an inert gas inlet for receiving inert gas, an inert gas outlet, and an inert gas passage establishing fluid communication between the inert gas inlet and the inert gas outlet,
[0010] - a double-walled connection pipe having a first end and a second end, the first end being connectable to the first connection block, the second end being connectable to the second connection block, the connection pipe comprising an inner pipe for transporting liquid fuel to the engine and an outer pipe arranged around the inner pipe such that a leakage space is formed between the inner pipe and the outer pipe, wherein at the first end of the connection pipe the inner pipe is connectable to the fuel inlet of the first connection block and at the second end of the connection pipe the inner pipe is connectable to the fuel outlet of the second connection block, and
[0011] - an inert gas pipe having a first end and a second end, the first end being connectable to the inert gas outlet or inlet of the first connection block, the second end being connectable to the inert gas inlet or outlet of the second connection block.
[0012] The second connection block further comprises a leakage passage having an inlet and an outlet, the inlet being configured to be arranged in fluid communication with the leakage space of the double-walled connection pipe, the leakage passage comprising a closure element having a closed position in which a flow between the inlet and the outlet is prevented and an open position in which a flow between the inlet and the outlet is allowed, the closure element being configured to move from the closed position to the open position when a pressure on the inlet side of the closure element exceeds a predetermined threshold value.
[0013] The pipe connection arrangement according to the invention can be used in a fuel supply system in which an inert atmosphere is maintained in the leakage space of the double-walled fuel supply pipe. The double-walled connection pipe can be a flexible pipe. By means of the inert gas pipe, inert gas can be supplied from one connection block to the other connection block while the leakage space of the double-walled connection pipe is kept free of inert gas during normal operation of the engine. Thus, the double-walled connection pipe is not exposed to inert gas, which allows a more free choice of the material of the outer surface of the inner pipe of the connection pipe and the material of the inner surface of the outer pipe of the connection pipe and increases the lifetime of the connection pipe. In case of a leak of the connection pipe, the leaking fuel can be drained via the leakage passage of the connection blocks and the leakage space can be purged with inert gas.
[0014] According to an embodiment of the application, the second connection block is configured such that the inner tube of the double-walled fuel supply pipe can be connected to the fuel inlet of the second connection block and the leakage space formed between the inner tube and the outer tube of said fuel supply pipe can be connected to the inert gas outlet or inlet of the second connection block, and the outlet of the leakage channel is arranged such that the leakage channel is in fluid communication with the leakage space of the fuel supply pipe in the mounted state of the fuel supply pipe.
[0015] Thus, the leakage space of the fuel supply pipe can be used for receiving leaked fuel from the leakage space of the connection pipe and for delivering inert gas to or from the second connection block.
[0016] According to an embodiment of the application, the second connection block comprises a leakage indicator connected to the leakage channel. This allows for easy detection of a leak of the connection pipe.
[0017] According to an embodiment of the application, the first connection block further comprises a second fuel inlet, a second fuel outlet, a second fuel channel establishing fluid communication between said second fuel inlet and second fuel outlet, a second inert gas inlet, a second inert gas outlet, a second inert gas channel establishing fluid communication between said second inert gas inlet and inert gas outlet, and the second connection block comprises a second fuel inlet, a second fuel outlet, a second fuel channel establishing fluid communication between said second fuel inlet and second fuel outlet, a second inert gas inlet, a second inert gas outlet and a second inert gas channel establishing fluid communication between said second inert gas inlet and inert gas outlet. The pipe connection arrangement further comprises
[0018] - a second double-walled connection pipe having a first end connectable to said first connection block and a second end connectable to said second connection block, said second connection pipe comprising an inner tube for delivering liquid fuel from said engine and an outer tube arranged around said inner tube such that a leakage space is formed between said inner tube and said outer tube, wherein at said first end of said second connection pipe said inner tube is connectable to said second fuel outlet of said first connection block and at said second end of said second connection pipe said inner tube is connectable to said second fuel inlet of said second connection block, and
[0019] - a second inert gas pipe having a first end connectable to said second inert gas inlet or outlet of said first connection block and a second end connectable to said second inert gas outlet or inlet of said second connection block.
[0020] The second connection block further comprises a second leakage channel having an inlet and an outlet, the inlet being configured to be arranged in fluid communication with the leakage space of the second connection pipe, the second leakage channel comprising a closure element having a closed position in which a flow between the inlet and the outlet is prevented and an open position in which a flow between the inlet and the outlet is allowed, the closure element being configured to move from the closed position to the open position when a pressure on an inlet side of the closure element exceeds a predetermined threshold.
[0021] Thus, the pipe connection device can be configured to also convey fuel overflow from the engine, and the second connection pipe can be provided in a similar way as the first connection pipe, which has a leakage space that is free of inert gas during normal operation of the engine but collects fuel that can leak.
[0022] According to an embodiment of the invention, the second connection block is configured such that the inner pipe of the double-walled fuel return pipe can be connected to the second fuel outlet of the second connection block and the leakage space formed between the inner pipe and the outer pipe of the fuel return pipe can be connected to the second inert gas inlet or outlet of the second connection block, and the outlet of the second leakage channel is arranged such that the second leakage channel is in fluid communication with the leakage space of the fuel return pipe in the installed state of the fuel return pipe.
[0023] Thus, the leakage space of the fuel return pipe can be used to receive leaked fuel from the leakage space of the connection pipe and to transport inert gas to or from the second connection block.
[0024] According to an embodiment of the invention, the second connection block comprises a leakage indicator connected to the second leakage channel. This allows to easily detect a leakage of the second connection pipe.
[0025] The fuel supply system according to the invention comprises a pipe connection device as defined above and a fuel supply pipe connected to the second connection block.
[0026] The internal combustion engine according to the invention comprises a fuel supply system as defined above.
[0027] The method for operating an internal combustion engine as defined above according to the invention comprises the steps of
[0028] - filling the leakage space of the fuel supply system with inert gas in addition to the leakage space between the second connection block and the first connection block to create an inert atmosphere in the filled leakage space,
[0029] - supplying fuel to the engine via the fuel supply pipe, and
[0030] - maintaining the inert atmosphere in the leakage space when operating the engine with fuel supplied via the fuel supply pipe.
[0031] According to embodiments of the application, a leakage into a leakage space of a connection pipe is monitored, and in case a leakage is detected, the leakage space is purged by introducing an inert gas into the leakage space. BRIEF DESCRIPTION OF DRAWINGS
[0032] Embodiments of the application are described in more detail below with reference to the drawings, in which
[0033] Figure 1 a fuel supply system of an internal combustion engine is schematically shown,
[0034] Figure 2 a perspective view of a pipe connection arrangement according to embodiments of the application is shown,
[0035] Figure 3 a pipe connection arrangement according to embodiments of the application is schematically shown,
[0036] Figure 4 a flow chart of a method according to the application is shown,
[0037] Figure 5 a partial view of a pipe connection arrangement of Figure 2 is shown,
[0038] Figure 6 a partial sectional view of a pipe connection arrangement of Figure 2 is shown,
[0039] Figure 7 a sectional view of a connection block is shown, and
[0040] Figure 8 another sectional view of a connection block is shown. DETAILED DESCRIPTION
[0041] Figure 1 A fuel supply system according to embodiments of the application is schematically shown. The fuel supply system supplies a liquid fuel to an internal combustion engine 1. The engine 1 is a piston engine. The engine 1 is a large piston engine, e.g. a main engine or an auxiliary engine of a ship or a power plant engine. The engine has a cylinder diameter of at least 150 mm and / or a rated power of at least 500 kW.
[0042] Figure 1 The fuel supply system of supplies a first liquid fuel to the engine 1. The first fuel can be, e.g., methanol. However, the first fuel can also be some other fuel. In particular, the first fuel can be highly toxic and / or highly flammable, so that specific protective measures are required for preventing exposure of a person operating the engine 1 to the fuel and / or for reducing the fire risk.
[0043] The engine 1 can be provided with two or more separate or partly separate fuel supply systems. For example, the engine 1 can be operated using a second fuel, and the engine 1 can be provided with a separate fuel supply system for supplying the second fuel to the engine 1. The second fuel can be a liquid fuel, such as light fuel oil, or a gaseous fuel, such as natural gas. The engine 1 can also be operated using a mixture of different fuels or using one fuel as a main fuel and another fuel as a pilot fuel for the main fuel.
[0044] The fuel supply system comprises a double-walled fuel line 2 for supplying fuel to the engine 1. The fuel line 2 comprises an inner pipe 3 configured to transport a first fuel and an outer pipe 4 arranged around the inner pipe 3 such that an annular leakage space 5 is formed between the inner pipe 3 and the outer pipe 4. The annular leakage space 5 need not be continuous but can be divided into two or more sections. The fuel supply system comprises at least one fuel pump 19 for pressurizing the first fuel.
[0045] The fuel supply system further comprises leakage detection means 6, 7, 8, 9, 14, 15, 16 for detecting leakage of the first fuel into the leakage space 5, means 33, 43, 53 for supplying inert gas into the leakage space 5 to purge the leakage space 5 upon detection of leakage into the leakage space 5, and means 31, 32, 41, 42, 51, 52 for supplying inert gas into the leakage space 5 to maintain an inert atmosphere within the leakage space 5 when the engine 1 is operated using the first fuel.
[0046] Thus, in the fuel supply system according to the application, inert gas is used for two purposes: During operation of the engine 1 using the first fuel, the leakage space 5 is kept filled with inert gas. The inert atmosphere in the leakage space 5 effectively reduces the fire risk when fuel leaks from the inner pipe 3 into the leakage space 5. In case of a leak, the inert gas can be used to purge the leakage space 5 to remove the leaked fuel from the leakage space 5. The inert gas can be, for example, nitrogen.
[0047] The leakage detection means can comprise one or more pressure sensors 14, 15, 16 and / or one or more liquid level sensors 6, 7, 8, 9. The liquid level sensors 6, 7, 8, 9 can detect even small amounts of liquid fuel leakage, but need to be positioned such that leaked fuel reaches at least one of the liquid level sensors. The pressure sensors 14, 15, 16 can be positioned more freely, but do not necessarily detect as small amounts of leakage as the liquid level sensors 6, 7, 8, 9. On the other hand, the pressure sensors 14, 15, 16 can also be configured to detect leakage from the leakage space 5.
[0048] The leakage space 5 can be divided into two or more separate parts 5A, 5B, 5C, 5D, so that a leakage into one of the parts 5A, 5B, 5C, 5D can be detected independently of the other parts. This allows detecting the location of a fuel supply system leakage. Also, in case of a leakage, it is not necessary to purge the entire leakage space 5, but it is sufficient to purge the affected part of the leakage space 5.
[0049] In Figure 1 In embodiments, different functions of the fuel supply system are arranged in the leakage unit 20. This provides a convenient way of filling the leakage space 5 with inert gas, monitoring the leakage, and purging the leakage space 5. However, the leakage unit 20 is not essential, and the fuel supply system can be implemented without the leakage unit 20.
[0050] The leakage unit 20 comprises leakage detection means 6, 7, 8, 9, 14, 15, 16 for detecting a leakage into the leakage space 5. The fuel line 2 comprises a first fuel supply part 2A extending from the fuel pump 19 to the leakage unit 20, a second fuel supply part 2B extending from the leakage unit 20 to the engine 1, a first overflow part 2C extending from the engine 1 to the leakage unit 20, and a second overflow part 2D extending downstream from the leakage unit 20. The leakage unit 20 divides the leakage space 5 into two or more separate parts 5A, 5B, 5C, 5D.
[0051] The first fuel is supplied to the engine 1 via the first fuel supply part 2A and the second fuel supply part 2B. Excess fuel from the engine 1 flows to the overflow tank via the overflow parts 2C, 2D.
[0052] In the embodiment of the figures, the leakage space 5 comprises four parts 5A, 5B, 5C, 5D. The leakage space parts 5B, 5C of the second fuel supply part 2B and the first overflow part 2C are in fluid communication with each other, thus not completely separated from each other. The fuel supply system is provided with a first pressure sensor 14, a second pressure sensor 15, and a third pressure sensor 16 serving as leakage detection means. The first pressure sensor 14 is configured to monitor the pressure in the leakage space part 5A of the first fuel supply part 2A, the second pressure sensor 15 is configured to monitor the pressure in the leakage space part 5D of the second overflow part 2D, and the third pressure sensor 16 is configured to monitor the pressure in the leakage space parts 5B, 5C of the second fuel supply part 2B and the first overflow part 2C.
[0053] The leakage unit 20 further comprises a leakage detection space 10, 11, 12, 13 arranged in fluid communication with each leakage space portion 5A, 5B, 5C, 5D of the leakage space 5 and a level sensor 6, 7, 8, 9 arranged to detect the presence of liquid in each leakage detection space 10, 11, 12, 13. The leakage unit 20 is arranged such that it forms the lowest part of the fuel supply system and fuel leaking into the leakage space 5 thus flows by gravity to the leakage unit 20.
[0054] The leakage unit 20 further comprises an outlet and a drain valve for emptying each leakage detection space 10, 11, 12, 13.
[0055] For filling the leakage space 5 with inert gas, the leakage space 5 is connected to an inert gas source 48. The inert gas can be stored in a tank at a pressure that is at least as high as the pressure required for purging the leakage space 5. Alternatively, a pump can be provided between the inert gas tank and the leakage space 5 to increase the pressure of the inert gas. The pressure for purging the leakage space 5 can for example be in the range of 600-1200 kPa.
[0056] Each individual portion of the leakage space 5 is connected to the inert gas source 48 via a filling valve 31, 41, 51. The filling valves are controllable valves. In the embodiment of the figures, the fuel supply system comprises a first filling valve 31 for controlling the supply of inert gas into the leakage space portion 5A of the first fuel supply portion 2A, a second filling valve 41 for controlling the supply of inert gas into the leakage space portion 5D of the second overflow portion 2D, and a third filling valve 51 for controlling the supply of inert gas into the leakage space portions 5B, 5C of the second fuel supply portion 2B and the first overflow portion 2C. Each inert gas line for supplying inert gas into the leakage space 5 is also provided with a pressure reduction valve 32, 42, 52 for reducing the pressure of the inert gas to a desired pressure level. The pressure of the inert gas supplied into the leakage space 5 for maintaining an inert atmosphere can for example be in the range of 150-400 kPa.
[0057] For purging the leakage space 5, the fuel supply system is provided with a purge valve 33, 43, 53 for each individual portion of the leakage space for supplying inert gas into the respective portion 5A, 5B, 5C, 5D at a higher pressure. In the embodiment of the figures, the fuel supply system thus comprises a first purge valve 33, a second purge valve 43 and a third purge valve 53. Via the purge valves 33, 43, 53, inert gas can be supplied into the leakage space 5 at a higher pressure than via the filling valves 31, 41, 51.
[0058] If the pressure of the inert gas can be adjusted as needed, the same valves can be used as purge valves and filling valves.
[0059] To prevent vibrations of the engine 1 from being transmitted to all components of the fuel supply system, the fuel supply system is provided with flexible parts. The flexible parts of the fuel supply system are arranged between the first connection block 120 and the second connection block 140. The first connection block 120 is rigidly attached to the engine 1 and the second connection block 140 is arranged at a distance from the engine 1.
[0060] The first connection block 120 comprises a first fuel inlet 121 for receiving fuel, a first fuel outlet 122, a first fuel passage 123 establishing fluid communication between the first fuel inlet 121 and the first fuel outlet 122, a first inert gas inlet 124, a first inert gas outlet 125 and a first inert gas passage 126 establishing fluid communication between the first inert gas inlet 124 and the first inert gas outlet 125.
[0061] The second connection block 140 comprises a first fuel inlet 141 for receiving fuel, a first fuel outlet 142, a first fuel passage 143 establishing fluid communication between the first fuel inlet 141 and the first fuel outlet 142, a first inert gas inlet 144 for receiving inert gas, a first inert gas outlet 145 and a first inert gas passage 146 establishing fluid communication between the first inert gas inlet 144 and the first inert gas outlet 145.
[0062] The fuel supply system further comprises a first double-walled connection pipe 170 having a first end connectable to the first connection block 120 and a second end connectable to the second connection block 140, the first connection pipe 170 comprising an inner pipe 171 for transporting liquid fuel to the engine 1 and an outer pipe 172 arranged around the inner pipe 171 such that a leakage space 173 is formed between the inner pipe 171 and the outer pipe 172. The first end of the inner pipe 171 of the first connection pipe 170 is connected to the first fuel inlet 121 of the first connection block 120 and the second end of the inner pipe 171 of the first connection pipe 170 is connected to the first fuel outlet 142 of the second connection block 140. The inner pipe 171 and the outer pipe 172 of the first connection pipe 170 are flexible. Thus, the first connection pipe 170 allows for a mutual movement of the first connection block 120 and the second connection block 140. This ensures that vibrations of the engine 1 do not cause a leakage in the fuel supply system.
[0063] The fuel supply system further comprises a first inert gas pipe 174 having a first end connected to the first inert gas outlet 125 of the first connection block 120 and a second end connectable to the first inert gas inlet 144 of the second connection block 140. The first inert gas pipe 174 is also flexible.
[0064] The second connection block 140 further comprises a first leakage channel 149 having an inlet 147 and an outlet 148. The inlet 147 is arranged in fluid communication with the leakage space 173 of the first double-walled connection pipe 170. The first leakage channel 149 comprises a closure element 150 having a closed position in which flow between the inlet 147 and the outlet 148 is prevented and an open position in which flow between the inlet 147 and the outlet 148 is allowed. The closure element 150 is configured to move from the closed position to the open position when the pressure on the inlet side of the closure element 150 exceeds a predetermined threshold. The opening pressure of the closure element 150 can for example be in the range of 100-300 kPa. When the opening pressure of the closure element 150 is exceeded and the closure element 150 has moved to the open position, it will remain in the open position until manually moved back to the closed position.
[0065] In the embodiment of the drawings, the inner pipe 176 of the double-walled fuel supply pipe 175 is connected to the first fuel inlet 141 of the second connection block 140 and the leakage space 178 formed between the inner pipe 176 and the outer pipe 177 of the fuel supply pipe 175 is connected to the first inert gas outlet 145 of the second connection block 140. The outlet 148 of the first leakage channel 149 is arranged such that the first leakage channel 149 is in fluid communication with the leakage space 178 of the fuel supply pipe 175.
[0066] The second connection block 140 further comprises a first leakage indicator 161 connected to the first leakage channel 149. In the embodiment of the drawings, the first leakage indicator 161 is a pin that pops out when the pressure in the first leakage channel 149 exceeds a predetermined threshold. In the embodiment of the drawings, the leakage indicator 161 is connected to the closure element 150 of the first leakage channel 149 and indicates a leakage when the closure element 150 moves to the open position.
[0067] In the embodiment of the drawings, the first connection block 120 further comprises a second fuel inlet 131, a second fuel outlet 132, a second fuel channel 133 establishing fluid communication between the second fuel inlet 131 and the second fuel outlet 132, a second inert gas inlet 134, a second inert gas outlet 135 and a second inert gas channel 136 establishing fluid communication between the second inert gas inlet 134 and the second inert gas outlet 135.
[0068] The second connection block 140 comprises a second fuel inlet 151, a second fuel outlet 152, a second fuel channel 153 establishing fluid communication between the second fuel inlet 151 and the second fuel outlet 152, a second inert gas inlet 154, a second inert gas outlet 155 and a second inert gas channel 156 establishing fluid communication between the second inert gas inlet 154 and the second inert gas outlet 155.
[0069] The fuel supply system comprises a second double-walled connection pipe 180 having a first end and a second end. The first end is connected to the first connection block 120 and the second end is connected to the second connection block 140. The second connection pipe 180 comprises an inner pipe 181 for transporting liquid fuel from the engine 1 and an outer pipe 182 arranged around the inner pipe 181 such that a leakage space 183 is formed between the inner pipe 181 and the outer pipe 182. The first end of the inner pipe of the second connection pipe 180 is connected to the second fuel outlet 132 of the first connection block 120 and the second end of the inner pipe 181 of the second connection pipe 180 is connected to the second fuel inlet 151 of the second connection block 140.
[0070] The fuel supply system further comprises a second inert gas pipe 184 having a first end and a second end. The first end is connected to the second inert gas inlet 134 of the first connection block 120 and the second end is connected to the second inert gas outlet 155 of the second connection block 140. The second inert gas pipe 184 is a flexible pipe.
[0071] The second connection block 140 further comprises a second leakage passage 159 having an inlet 157 and an outlet 158. The inlet 157 is arranged in fluid communication with the leakage space 183 of the second connection pipe 180. The second leakage passage 159 comprises a closure element 160 having a closed position in which flow between the inlet 157 and the outlet 158 is prevented and an open position in which flow between the inlet 157 and the outlet 158 is allowed. The closure element 160 is configured to move from the closed position to the open position when the pressure on the inlet side of the closure element 160 exceeds a predetermined threshold value. The closure element 160 of the second leakage passage 159 functions in the same way as the closure element 150 of the first leakage passage 149.
[0072] The inner pipe 186 of the double-walled fuel return pipe 185 is connected to the second fuel outlet 152 of the second connection block 140 and the leakage space 188 formed between the inner pipe 186 and the outer pipe 187 of the fuel return pipe 185 is connected to the second inert gas inlet 154 of the second connection block 140. The outlet 158 of the second leakage passage 159 is arranged in fluid communication with the leakage space 188 of the fuel return pipe 185.
[0073] The second connection block 140 comprises a second leakage indicator 162 connected to the second leakage passage 159. The second leakage indicator 162 can be similar to the first leakage indicator 161.
[0074] The fuel supply pipe 175 and the first connection pipe 170 form part of a second fuel supply portion 2B of the fuel line 2. The fuel return pipe 185 and the second connection pipe 180 form part of a first spill portion 2C of the fuel line 2.
[0075] The inert gas introduced into the leakage space 188 of the fuel return pipe 185 can flow via the second connection block 140 into the second inert gas pipe 184 and further via the first connection block 120 to the engine 1. Inert gas can flow from the engine 1 to the first connection block 120 and via the first inert gas pipe 174 to the second connection block 140 and further into the leakage space 178 of the fuel supply pipe 175.
[0076] During normal operation of the engine 1, no inert gas is present in the leakage spaces 173, 183 of the first and second connection pipes 170, 180. This allows the outer surface of the inner pipes 171, 181 of the first and second connection pipes 170, 180 to be made of a material which is not subjected to long-term exposure to inert gas.
[0077] In a first step 101 of the method according to the application, the leakage spaces of the double-walled pipes of the fuel supply system are filled with inert gas to create an inert atmosphere in the filled leakage spaces. However, the leakage spaces 173, 183 of the first and second connection pipes 170, 180 between the first and second connection blocks 120, 140 are not filled with inert gas. In a second step 102 of the method, fuel is supplied to the engine via the fuel line 2 of the fuel supply system. In a third step 103 of the method, the inert atmosphere in the leakage spaces of the fuel supply system is maintained when the engine is operated using the fuel supplied via the fuel line 2.
[0078] In the event of a leak from the fuel line 2 into the leakage space 173, 183 of one of the connection pipes 170, 180, the pressure in the respective leakage space 173, 183 rises. When the opening pressure of the closure element 150, 160 of the leak passage 149, 159 is exceeded, the closure element 150, 160 moves into the open position and the leaking fuel can flow into the leakage space 178, 188 of the fuel supply pipe 175 or the fuel return pipe 185 and further to the leak detection unit 20. The leak detection device of the leak detection unit 20 can detect the leak. The leak is also indicated by the respective leak indicator 161, 162 of the second connection block 140. When the closure element 150, 160 moves into the open position, the inert gas in the leakage space 178, 188 of the fuel supply pipe 175 or the fuel return pipe 185 can flow into the leakage space 173, 183 of the respective connection pipe 170, 180.
[0079] When a leak is detected, an alarm can be triggered and the engine 1 can be switched to use another fuel or shut down.
[0080] In case a leak into the leak space 173, 183 of the first and second connection pipes 170, 180 is detected, the respective leak space 173, 183 can be purged by introducing inert gas into the leak space 173, 183 at a higher pressure than the pressure of the inert atmosphere maintained during normal operation of the engine 1. After the system purge, the leak space is evacuated and the closure elements 150, 160 are movable back to the closed position.
[0081] In the embodiment of the drawing, the inert gas is introduced into the leak space between the leak unit 20 and the engine 1 via the leak space 188 of the fuel return pipe 185. However, the inert gas can also be supplied via the leak space 178 of the fuel supply pipe 175.
[0082] In the embodiment of the drawing, the connection pipes 170, 180 for both fuel supply and fuel return are arranged between the first and second connection blocks 120, 140. However, instead of having a common connection block 120, 140 for fuel supply and fuel return, the fuel supply system can also be provided with separate connection blocks for fuel supply and fuel return.
Claims
1. A pipe connection device for a fuel supply system of an internal combustion engine (1), the pipe connection device comprising: - A first connecting block (120), configured to be rigidly attached to the engine (1), the first connecting block (120) including a fuel inlet (121) for receiving fuel, a fuel outlet (122), a fuel passage (123) establishing fluid communication between the fuel inlet (121) and the fuel outlet (122), an inert gas inlet (124), an inert gas outlet (125), and an inert gas passage (126) establishing fluid communication between the inert gas inlet (124) and the inert gas outlet (125). - A second connecting block (140), configured to be disposed at a distance from the engine (1), the second connecting block (140) including a fuel inlet (141) for receiving fuel, a fuel outlet (142), a fuel passage (143) establishing fluid communication between the fuel inlet (141) and the fuel outlet (142), an inert gas inlet (144) for receiving inert gas, an inert gas outlet (145), and an inert gas passage (146) establishing fluid communication between the inert gas inlet (144) and the inert gas outlet (145). - A double-walled connecting pipe (170) having a first end and a second end, the first end being connectable to a first connecting block (120) and the second end being connectable to a second connecting block (140), the connecting pipe (170) including an inner pipe (171) for supplying liquid fuel to the engine (1) and an outer pipe (172) arranged around the inner pipe (171) such that a leakage space (173) is formed between the inner pipe (171) and the outer pipe (172), wherein at the first end of the connecting pipe (170), the inner pipe (171) is connectable to the fuel inlet (121) of the first connecting block (120), and at the second end of the connecting pipe (170), the inner pipe (171) is connectable to the fuel outlet (142) of the second connecting block (140), and - Inert gas tube (174), the inert gas tube having a first end and a second end, the first end being able to be connected to the inert gas outlet (125) or inlet (124) of the first connecting block (120), and the second end being able to be connected to the inert gas inlet (144) or outlet (145) of the second connecting block (140). in, The second connecting block (140) further includes a leakage passage (149) having an inlet (147) and an outlet (148), the inlet (147) being configured to be in fluid communication with the leakage space (173) of the double-walled connecting pipe (170), the leakage passage (149) including a closing element (150) having a closed position and an open position, in which flow between the inlet (147) and the outlet (148) is blocked, and in which flow between the inlet (147) and the outlet (148) is permitted, the closing element (150) being configured to move from the closed position to the open position when the pressure on the inlet side of the closing element (150) exceeds a predetermined threshold.
2. The pipe connection device according to claim 1, wherein the second connection block (140) is configured such that the inner tube (176) of the double-walled fuel supply pipe (175) can be connected to the fuel inlet (141) of the second connection block (140), and the leakage space (178) formed between the inner tube (176) and the outer tube (177) of the fuel supply pipe (175) can be connected to the inert gas outlet (145) or inlet (144) of the second connection block (140), and the outlet (148) of the leakage channel (149) is arranged such that the leakage channel (149) is in fluid communication with the leakage space (178) of the fuel supply pipe (175) in the installed state of the fuel supply pipe (175).
3. The pipe connection device according to claim 1 or 2, wherein the second connection block (140) includes a leak indicator (161) connected to the leak channel (149).
4. The pipe connection device according to any one of claims 1 to 3, wherein the first connecting block (120) further comprises a second fuel inlet (131), a second fuel outlet (132), a second fuel passage (133) establishing fluid communication between the second fuel inlet (131) and the second fuel outlet (132), a second inert gas inlet (134), a second inert gas outlet (135), and a second inert gas passage (136) establishing fluid communication between the second inert gas inlet (134) and the inert gas outlet (136), and the second connecting block (140) comprises a second fuel inlet (151), a second fuel outlet (152), a second fuel passage (153) establishing fluid communication between the second fuel inlet (151) and the second fuel outlet (152), a second inert gas inlet (154), a second inert gas outlet (155), and a second inert gas passage (156) establishing fluid communication between the second inert gas inlet (154) and the inert gas outlet (155), and the pipe connection device further comprises - A second double-walled connecting pipe (180) having a first end and a second end, the first end being connectable to the first connecting block (120), and the second end being connectable to the second connecting block (140). The second connecting pipe (180) includes an inner pipe (181) for conveying liquid fuel from the engine (1) and an outer pipe (182) arranged around the inner pipe (181) such that a leakage space (183) is formed between the inner pipe (181) and the outer pipe (182). At the first end of the second connecting pipe (180), the inner pipe (181) is connectable to the second fuel outlet (132) of the first connecting block (120), and at the second end of the second connecting pipe (180), the inner pipe (181) is connectable to the second fuel inlet (151) of the second connecting block (140). - Second inert gas tube (184), the second inert gas tube has a first end and a second end, the first end can be connected to the second inert gas inlet (134) or outlet (135) of the first connecting block (120), and the second end can be connected to the second inert gas outlet (155) or inlet (154) of the second connecting block (140). in, The second connecting block (140) further includes a second leakage channel (159) having an inlet (157) and an outlet (158), the inlet (157) being configured to be in fluid communication with the leakage space (183) of the second connecting pipe (180), the second leakage channel (159) including a closing element (160) having a closed position and an open position, wherein flow between the inlet (157) and the outlet (158) is blocked in the closed position and flow between the inlet (157) and the outlet (158) is permitted in the open position, the closing element (160) being configured to move from the closed position to the open position when the pressure on the inlet side of the closing element (160) exceeds a predetermined threshold.
5. The pipe connection device according to claim 4, wherein the second connection block (140) is configured such that the inner tube (186) of the double-walled fuel return pipe (185) can be connected to the second fuel outlet (152) of the second connection block (140), and the leakage space (188) formed between the inner tube (186) and the outer tube (187) of the fuel return pipe (185) can be connected to the second inert gas inlet (154) or outlet (155) of the second connection block (140), and the outlet (158) of the second leakage channel (159) is arranged such that the second leakage channel (159) is in fluid communication with the leakage space (188) of the fuel return pipe (185) in the installed state of the fuel return pipe (185).
6. The pipe connection device according to any one of claims 3 to 5, wherein the second connection block (140) includes a leak indicator (162) connected to the second leak channel (159).
7. A fuel supply system for an internal combustion engine (1), wherein the fuel supply system includes a pipe connection device according to any one of the preceding claims and a fuel supply pipe (175) connected to the second connection block (140).
8. An internal combustion engine (1), the internal combustion engine comprising the fuel supply system according to claim 7.
9. A method of operating an internal combustion engine (1) according to claim 8, wherein the method comprises the following steps - Except for the leakage space (173, 183) between the second connecting block (140) and the first connecting block (140), the leakage space (178, 188) of the fuel supply system is filled with inert gas to generate an inert atmosphere (101) in the filled leakage space (178, 188). - Fuel (102) is supplied to the engine via the fuel supply pipe (175). - When the engine (1) is operated using fuel supplied via the fuel supply pipe (175), the inert atmosphere (103) in the leakage space (178, 188) is maintained.
10. The method according to claim 9, wherein leakage to the leakage space (173) of the connecting pipe (170) is monitored, and if leakage is detected, the leakage space (173) is purged by introducing an inert gas into the leakage space (173).