Tank systems and how to inspect isolation valves in tank systems

Abstract

[Solution] A method for inspecting a switchable isolation valve of a valve device connecting a tank container to a piping system includes controlling the isolation valve to switch the extraction path of the valve device connecting the piping system and the tank container from a closed position in which the isolation valve closes the extraction path to an open position in which the isolation valve opens the extraction path, detecting a pressure transition in a tank side area of ​​the extraction path extending between the tank container and the isolation valve, determining whether the pressure transition detected after controlling the isolation valve includes a pressure drop, and outputting an error signal if it is determined that the pressure transition detected after controlling the isolation valve does not include a pressure drop.

Description

[Technical Field]

[0001] The present invention relates to a tank system, in particular a tank system for storing a gaseous fuel, such as hydrogen, and for supplying the gaseous fuel to a consumer system, and to a method for testing an isolation valve in a tank system. [Background technology]

[0002] Hydrogen and other gaseous fuels can be used in mobile applications, especially in road vehicles, to operate propulsion systems. This includes not only the operation of fuel cells, but also internal combustion engines or other heat engines. Stationary applications also favor the use of gaseous fuels for energy generation. For this purpose, the gas is typically stored in a tank system with one or more tank vessels and supplied to a consumer system, such as a fuel cell or internal combustion engine, via a piping system connected to the one or more tank vessels.

[0003] Patent Document 1 describes a supply system for a fuel cell in which multiple tanks are connected in parallel to a piping system that supplies the fuel cell via respective outlet pipes. Each outlet pipe is provided with a switchable isolation valve to connect or isolate the respective tank from the piping system. When the system is started, only one of the isolation valves is opened first to increase the pressure in the piping system, followed by the remaining valves. This serves the purpose of reducing wear on the valves by reducing the pressure difference between the tanks and the high-pressure piping system when the remaining valves open.

[0004] In general, to increase operational reliability, it is desirable to ensure that the isolation valve is open when the system is started, whether the system has only one tank vessel or multiple tank vessels. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 7,367,349 B2 Summary of the Invention

[0006] Against this background, the present invention provides a method having the features of claim 1 as well as a tank system having the features of claim 8.

[0007] In a first aspect of the present invention, a method for testing a switchable isolation valve of a valve device connecting a tank container to a piping system is provided, wherein gas is stored in the tank container at a first pressure and a second pressure lower than the first pressure is present in the piping system, the method comprising controlling an isolation valve to switch an outlet line of the valve device connecting the piping system to the tank container from a closed position in which the isolation valve closes the outlet line to an open position in which the isolation valve opens the outlet line, detecting a pressure profile in a tank-side section of the outlet line extending between the tank container and the isolation valve, determining whether the pressure profile detected after controlling the isolation valve includes a pressure drop, and outputting an error signal if it is determined that the pressure profile detected after controlling the isolation valve does not include a pressure drop.

[0008] In a second aspect of the present invention, a tank system comprises at least one tank container for storing a gas, in particular hydrogen, a piping system for supplying a consumer system, such as a fuel cell or a heat engine, a valve device having an outlet path connecting the tank container to the piping system and having a switchable isolation valve arranged in the outlet path that is switchable between a closed position for closing the outlet path and an open position for opening the outlet path, a pressure sensor connected to a tank-side section of the outlet path extending between the tank container and the isolation valve and set up to detect the pressure in the tank-side section of the outlet path, and a control device in signal connection with the valve device and the pressure sensor and set up to instruct the tank system to perform each step of the method according to any one of claims 1 to 7.

[0009] The idea behind the present invention is to detect a pressure curve on the tank side of the isolation valve and evaluate it after the valve has been controlled. Since a lower pressure exists in the piping system than in the tank vessel and therefore on the tank side of the isolation valve before the isolation valve opens, the opening of the isolation valve leads to a temporary drop in pressure on the tank side. That is, when the isolation valve switches from the closed position to the open position, an undershoot occurs in the pressure curve in the tank-side section of the outlet path of the valve device. This temporary drop in pressure can be determined or detected by the control device using the pressure signal provided by the pressure sensor. If such a pressure drop is detected, it can be assumed that the respective isolation valve has not been switched from the closed position to the open position as a result of the control. If no pressure drop is detected, it can be assumed that the isolation valve has not been switched from the closed position to the open position as a result of the control.

[0010] One advantage of the present invention is that it reliably identifies isolation valves that are not switching.

[0011] Preferred embodiments and developments emerge from the further dependent claims and from the description given with reference to the drawing figures.

[0012] In some embodiments, controlling the isolation valve may include generating a first opening force to open the isolation valve, and if it is determined that the pressure transition detected after controlling the isolation valve does not include a pressure drop, the isolation valve may be controlled again with a second opening force higher than the first opening force, and the steps of detecting and determining the pressure transition may be performed again. Accordingly, if it is determined that the isolation valve does not open during the first control, the isolation valve may be controlled again with a higher opening force. This can further increase operational reliability, since opening the isolation valve with a higher opening force can ensure that the tank system remains fully functional.

[0013] In some embodiments, it may be intended that the output of the error signal is performed only if it is determined anew that the pressure profile detected after the new control of the isolation valve with the second opening force does not include a pressure drop. Optionally, a first error signal can be output if no pressure drop is determined in the pressure profile detected after the first control of the isolation valve, and a second error signal can be output if it is determined anew that the pressure profile detected after the new control of the isolation valve with the second opening force does not include a pressure drop.

[0014] In some embodiments, the isolation valve may be intended to be configured as an electrically controllable normally closed solenoid valve, and generating the first opening force includes passing a first control current through the isolation valve, and generating the second opening force includes passing a second control current through the isolation valve, the second control current being higher than the first control current.

[0015] In some embodiments, the output of the release signal may be intended to occur when it is determined that the pressure transition detected after controlling the isolation valve includes a pressure drop, for example, the output of the release signal may include generating a release message and writing the release message to a data storage device.

[0016] In some embodiments, it may be intended that multiple tank containers are connected to a piping system via multiple valve devices, each having a switchable isolation valve, and each isolation valve is controlled to switch from a closed position to an open position. A pressure profile in a tank-side section of the outlet path of each isolation valve is detected after controlling the respective isolation valve. It is determined for each isolation valve whether the pressure profile detected after controlling the isolation valve includes a pressure drop. An error signal is output for each isolation valve for which it is determined that the pressure profile detected after controlling the respective isolation valve does not include a pressure drop. In particular, with multiple tank containers, if one of the isolation valves does not open, this can lead to undesirable effects. On the one hand, gas stored in the tank container whose isolation valve does not open cannot be used for the consumer system. On the other hand, this can lead to uneven emptying of the tank containers. If the isolation valve that did not open opens at a later time, for example, when the system is started up again, this can lead to pressure compensation and / or refilling of other tank containers. Such situations can be reliably avoided by the method.

[0017] In some embodiments, it may be intended that the isolation valves be controlled sequentially or simultaneously.

[0018] In some embodiments, determining whether the pressure transition detected after controlling the isolation valve includes a pressure drop may include determining the pressure gradient of the detected pressure transition, and may be intended to determine a pressure drop if the pressure gradient is less than zero within a preset time after the control.

[0019] In some embodiments, outputting the error signal may be intended to include generating an error message and writing the error message to a data storage device. Alternatively or additionally, outputting the error signal may be intended to include outputting a warning signal to a user interface. For example, an optical signal may be output to a display device or warning lamp of the user interface, or an acoustic or tactile signal may be output.

[0020] In some embodiments, the isolation valve may be intended to be configured as an electrically controllable normally closed solenoid valve.

[0021] In some embodiments, the tank system may be intended to have a plurality of tank vessels connected to the piping system via a plurality of valve arrangements, each having a switchable isolation valve.

[0022] Each feature and advantage disclosed herein in connection with one embodiment of the invention is also applicable to other embodiments.

[0023] The invention will now be described with reference to the figures of the drawings, in which: [Brief explanation of the drawings]

[0024] [Figure 1] FIG. 2 is a schematic diagram of a hydraulic piping diagram for a tank system according to an embodiment of the present invention. [Figure 2] FIG. 10 is a detailed view showing a valve arrangement of a tank system according to an embodiment of the present invention. [Figure 3] 1 is a flow diagram of a method according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0025] In the various figures, unless otherwise stated, the same reference numerals represent the same components or components with the same functions.

[0026] 1 shows a schematic representation of a tank system 100 for supplying a gaseous fuel, such as hydrogen, to a consumer system 200. The consumer system 200 may be, for example, a fuel cell or a heat engine. The tank system 100 may be applied, for example, in mobile applications, such as in a vehicle, although the invention is not so limited.

[0027] As shown by way of example in Figure 1, the tank system 100 comprises a plurality of tank containers 1, a piping system 2, a plurality of valve devices 3, and a control device 5. Optionally, a user interface 6 may also be provided. In Figure 1, purely by way of example, the tank system 100 is shown to comprise three tank containers 1. It is also conceivable that the tank system 100 comprises only one tank container 1, or a number of tank containers 1 different from three. Furthermore, by way of example, Figure 1 shows that each tank container 1 is provided with its own valve device 3, via which each tank container 1 is connected to the piping system 2. Alternatively, it is conceivable that multiple tank containers 1 are connected to the piping system 2 via a common valve device 3.

[0028] Tank vessel 1 generally defines an interior volume and may be configured, for example, for storing hydrogen under a rated pressure of up to 700 bar.

[0029] The piping system 2 may be, for example, a high pressure piping system 2 connected to a consumer system 200 via an optional medium pressure piping system 7, which is only symbolically shown as a block in Figure 1. As shown schematically in Figure 1, the tank 1 is connected to the piping system 2 in parallel with each other.

[0030] A valve device 3 is associated with each tank 1 and connects it to the piping system 2. FIG. 2 shows an exemplary structure of the valve device 3 in a highly simplified schematic diagram. As shown in FIG. 2, the valve device 3 has a first internal connection 3A connected to the internal volume of the tank 1 and an external connection 3C connected to the piping system 2. Optionally, a second internal connection 3B may also be provided. As shown in FIG. 2, the valve device 3 has a switchable isolation valve 30 and a pressure sensor 4. Optionally, a check valve 33 may additionally be provided. Also optionally, the valve device 3 may have a temperature sensor 35, which is shown in FIG. 2 purely by way of example.

[0031] The first internal connection 3A and the external connection 3C are connected to each other by a withdrawal path 31 in which an isolation valve 30, for example in the form of an electrically switchable normally closed solenoid valve, is arranged. The isolation valve 30 divides the withdrawal path 31 into a tank-side section 31A extending between the first internal connection 3A and the isolation valve 30 and a piping-side section 31B extending between the isolation valve 30 and the external connection 3C. The isolation valve 30 is switchable between a closed position and an open position. In FIG. 2, the isolation valve 30 is shown in the closed position. In this position, the isolation valve closes the withdrawal path, i.e., interrupts the fluid communication between the tank-side and piping-side sections 31A, 31B of the withdrawal path 31, thus preventing gas from the tank container 1 from flowing from the first internal connection 3A to the external connection 3C. In the open position, the isolation valve 30 opens the extraction path, i.e., establishes a fluid communication connection between the tank side and piping side sections 31A, 31B of the extraction path 31, allowing gas from the tank container 1 to flow from the first internal connection 3A to the external connection 3C.

[0032] 2, the second internal connection 3B may be connected to the external connection 3C by a filling path 32. An optional check valve 33 is disposed in the filling path 32 and is configured to allow flow only from the external connection 3C to the second internal connection 3B. When a higher pressure is generated in the piping system 2 than in the tank vessel 1, gas from the piping system 2 can flow from the external connection 3C through the second internal connection 3B into the tank vessel 1, even with the isolation valve 30 closed.

[0033] 2, the pressure sensor 4 is connected to the tank-side section 31A of the extraction path 31. In this way, the pressure sensor 4 can detect the pressure in the tank-side section 31A of the extraction path 31.

[0034] An optional temperature sensor 35 may be part of the valve device 3, as shown purely by way of example in Figure 2, where the temperature sensor 35 is arranged to be connected to the internal volume of the tank vessel 1. In this way, the temperature sensor 35 makes it possible to measure the temperature inside the tank vessel 1.

[0035] The control device 5 is shown only as a block in FIG. 1 and may in particular be an electronic control device 5. The control device 5 may, for example, have a processor 50 and a data storage device 51. The processor 50 may, for example, be embodied as a CPU, FPGA, ASIC, etc. The data storage device 51 may, in particular, be a non-volatile data storage device, such as a flash memory, SD memory, or hard disk. The data storage device 51 is readable by the processor 50 and may, for example, store software executable by the processor 50 that instructs it to generate output signals, for example in the form of control signals, based on input signals, for example in the form of measured values. The control device 5 is in signal connection with the valve device 3 and the respective pressure sensors 4 in a wired manner, for example via a data bus such as a CAN bus or USB, or wirelessly via WiFi, Bluetooth, etc.

[0036] In particular, the control device 5 may be configured to instruct the tank system 100 to perform a method M for testing the switchable isolation valve 30 of each valve device 3. The procedure of the method M for testing the switchable isolation valve 30 of each valve device 3 is shown diagrammatically in FIG. 3. The method M starts from an initial situation in which a gas, such as hydrogen, is stored in the tank vessel 1 at a first pressure and a second pressure lower than the first pressure exists in the piping system 2. The isolation valve 30 is then closed. Such an initial situation may occur, for example, before the start-up or startup of the consumer system 200 connected to the tank system 100. In the following, the method M will be explained with reference to the tank system 100 described above.

[0037] In a first step M1, the isolation valve 30 is controlled M1 by the control device 5, for example by the control device outputting a control signal to the isolation valve 30 to switch it from a closed position to an open position. The control signal may in particular instruct the generation of a first opening force for opening the isolation valve 30. If the isolation valve 30 is configured as an electrically controllable normally closed solenoid valve, as exemplarily shown in Figure 2, the generation of the first opening force may comprise passing a first control current through the isolation valve 30. If multiple tank containers 1 are provided with multiple valve devices 3, as exemplarily shown in Figure 1, the isolation valves 30 of the different valve devices 3 may be controlled sequentially or simultaneously.

[0038] In step M2, the pressure in the tank-side section 31A of the extraction path 31 is detected in time steps by the pressure sensor 4. In this way, the control device 5 receives a pressure signal representative of the pressure progression.

[0039] In step M3, the control device 5 determines whether the pressure profile detected after controlling the isolation valve 30 (step M1) includes a pressure drop. The control device 5 thus evaluates the pressure signal detected after controlling the isolation valve 30 to check whether the pressure signal indicates a pressure drop, at least in a time-limited manner. For example, the control device 5 can determine the pressure gradient of the detected pressure profile, and if the pressure gradient assumes a value lower than zero within a predetermined time after controlling, a pressure drop is determined or detected.

[0040] If it is determined in step M3 that the pressure transition detected after control M1 of the isolation valve 30 includes a pressure drop, as indicated by the symbol "+" in Figure 3, the method can proceed to step M5. The presence of a pressure drop indicates that the respective isolation valve 30 has opened in response to control (step M1). As a result of the pressure in the piping system 2 being lower than the pressure in the tank vessel 1, a time-limited pressure drop usually occurs after the isolation valve 30 opens. In this way, the pressure transition includes a type of undershoot.

[0041] In step M5, the control device 5 can, for example, output a release signal. This can, for example, involve generating a release message and writing the release message to the data store 51.

[0042] If it is determined in step M3 that the pressure profile detected after controlling the isolation valve 30 (step M1) does not include a pressure drop, as indicated by the symbol "-" in FIG. 3 , the method M proceeds directly to step M4, where the control device 5 outputs an error signal. The output of the error signal may include, for example, generating an error message and writing the error message to the data storage device 51. Alternatively or additionally, the control device 5 may output a warning signal to the user interface 6. For example, the user interface 6, which is only symbolically shown as a block in FIG. 1 , may have a display device or warning lamp instructed by the control device 5 to output an optical signal, or the user interface 6 may output an acoustic or tactile warning signal. The output of the error signal may be performed for each isolation valve 30 for which it was determined that the respective detected pressure profile did not include a pressure drop after controlling the respective isolation valve 30 (step M1), e.g., together with the index of the respective isolation valve.

[0043] Optionally, method M can proceed to step M31 first if step M3 determines that the pressure profile detected after controlling isolation valve 30 (step M1) does not include a pressure drop. In step M31, controller 5 can increment by 1 a value representing how many times isolation valve 30 has been controlled to switch from a closed position to an open position since isolation valve 30 most recently closed. If isolation valve 30 is switched to the closed position, this value is set to zero.

[0044] In step M32, the control device 5 checks whether this numerical value is smaller than a predetermined limit value. The limit value can be, for example, an integer between 2 and 10. If it is determined in step M32 that the numerical value is smaller than the limit value, as indicated by the symbol "+" in FIG. 3, the method can again proceed to step M1. In this case, the isolation valve 30 is again controlled by the control device 5 with a second opening force that is higher than the first opening force. For example, generating the second opening force can involve passing a second control current through the isolation valve 30 that is higher than the first control current. Steps M2 and M3 are then performed again as described above. If it is determined in step M3 that the pressure curve detected after the new control of the isolation valve 30 with the second opening force includes a pressure drop (symbol "+" in FIG. 3), the method proceeds to step M5. Otherwise, i.e. if it is determined that the pressure profile detected after the new control of the isolation valve with the second opening force does not contain a pressure drop, the method proceeds to steps M31 and M32. If it is determined in step M32 that the value is less than the limit value (sign "+"), the method can also proceed to steps M1 to M3, optionally with each iteration increasing the opening force further. If it is determined in step M32 that the value has reached the limit value (sign "-"), the method proceeds to step M4.

[0045] Optionally, the output of the error signal in step M4 is only performed if it is determined at least once again that the pressure profile detected after a new control of the isolation valve with the second opening force does not include a pressure drop.

[0046] Alternatively, step M4 can be performed whenever step M3 determines that the pressure profile detected after a new control of isolation valve 30 does not include a pressure drop, with steps M31 and M32 also being performed accordingly. For example, a first error signal can be output in step M4 whenever step M32 determines that the value is less than a limit value. If step M32 determines that the value has reached a limit value (symbol "-"), a second error signal can be output in step M4. The output of the first error signal can, for example, only involve generating an error message and writing it to data storage device 51, whereas the output of the second error signal can alternatively or additionally involve outputting a warning signal at the user interface.

[0047] Although the present invention has been described above by way of example, the present invention is not limited to this and can be modified in various ways. In particular, combinations of the above-described embodiments are also possible. [Explanation of symbols]

[0048] 1 tank container 2 Piping System 3 Valve device 6. User Interface 30 Isolation valve 31 Extraction route 31A Tank Side Area 31B Piping side area 51 Data storage device 100 Tank System 200 Consumer Device System M method M1 Control M2 detection M3 judgment M4 Output M5 Output

Claims

1. A method (M) for testing a switchable isolation valve (30) of a valve device (3) connecting a tank vessel (1) with a piping system (2), wherein a gas is stored in the tank vessel (1) at a first pressure and a second pressure lower than the first pressure is generated in the piping system (2), the method (M) comprising: The isolation valve (30) is controlled (M1) to switch the extraction path (31) of the valve device (3) connecting the piping system (2) and the tank container (1) from a closed position where the isolation valve (30) closes the extraction path (31) to an open position where the isolation valve (30) opens the extraction path (31); a pressure transition in a tank-side section (31A) of the extraction line (31) extending between the tank vessel (1) and the isolation valve (30) is detected (M2); determining (M3) whether or not a pressure drop is included in the pressure transition detected after the control (M1) of the isolation valve (31); outputting (M4) an error signal if it is determined that the pressure profile detected after controlling (M1) the isolation valve (31) does not include a pressure drop.

2. 2. The method according to claim 1, wherein the control (M1) of the isolation valve (30) comprises generating a first opening force for opening the isolation valve (30), and if it is determined that the pressure curve detected after the control (M1) of the isolation valve (31) does not include a pressure drop, the isolation valve (30) is again controlled (M1) with a second opening force higher than the first opening force, and the steps of detecting (M2) and determining (M3) the pressure curve are again performed, and an error signal (M4) is output only if it is determined again that the pressure curve detected after the new control of the isolation valve with the second opening force does not include a pressure drop.

3. 3. The method of claim 2, wherein the isolation valve (30) is configured as an electrically controllable normally closed solenoid valve, and wherein generating the first opening force comprises passing a first control current through the isolation valve (30), and generating the second opening force comprises passing a second control current through the isolation valve (30), the second control current being higher than the first control current.

4. 4. The method (M) of claim 1, further comprising: outputting (M5) a release signal when it is determined that the pressure transition detected after controlling (M1) the isolation valve (30) includes a pressure drop.

5. 5. The method according to claim 1, wherein a plurality of tank containers are connected to the piping system via a plurality of valve devices, each having a switchable isolation valve, and wherein each isolation valve is controlled to switch from a closed position to an open position; a pressure transition in the tank-side section of the withdrawal line of each isolation valve is detected after controlling each isolation valve; a determination is made for each isolation valve as to whether the pressure transition detected after controlling each isolation valve does not include a pressure drop; and an error signal is output for each isolation valve for which it is determined that the pressure transition detected after controlling each isolation valve does not include a pressure drop.

6. The method (M) of claim 5, wherein the isolation valves (30) are controlled sequentially or simultaneously.

7. 7. The method (M) according to any one of claims 1 to 6, wherein outputting (M4) an error signal comprises generating an error message and writing the error message to a data storage device (51) and / or outputting a warning signal to a user interface (6).

8. In the tank system (100), At least one tank vessel (1) for storing a gas, in particular hydrogen, a piping system (2) for supplying a consumer system (200); a valve device (3) having a withdrawal line (31) connecting the tank container (1) and the piping system (2), and a switchable isolation valve (30) arranged in the withdrawal line (31), which is switchable between a closed position for closing the withdrawal line (31) and an open position for opening the withdrawal line (31); a pressure sensor (4) connected to a tank-side section (31A) of the extraction line (31) extending between the tank vessel (1) and the isolation valve (30), and set up to detect pressure in the tank-side section (31A) of the extraction line (31A); a control device (5) in signal connection with the valve device (3) and the pressure sensor (4), and set up to instruct the tank system (100) to perform each step of the method (M) according to any one of claims 1 to 7.

9. 9. The tank system (100) of claim 8, wherein the isolation valve (30) is configured as an electrically controllable normally closed solenoid valve.

10. 10. The tank system (100) according to claim 8 or 9, comprising a plurality of tank containers (1) connected to the piping system (2) via a plurality of valve devices (3), each having a switchable isolation valve (30).

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