Cargo ship

Abstract

To load a fuel battery while suppressing expansion of hazardous area in a cargo transportation vessel where cargo hold is hazardous area.SOLUTION: A cargo transportation vessel includes: a hull; a hydrogen fuel tank for storing hydrogen fuel; a fuel battery power generation unit having a sealable casing and a fuel battery arranged inside it; and an electric power conversion device for supplying electric power generated by the fuel battery power generation unit to at least one of an electric motor for propulsion and an inboard electric power load. When an area from a portion positioned above the cargo hold in an upper deck of the hull to below a prescribed first height is stipulated as a hazardous place on a deck derived from the cargo, the hydrogen fuel tank is arranged in between front and back sides, i.e., from a front end to rear end of the cargo hold in the hull and the fuel cell electric power generation unit is arranged in between front and back sides, i.e., from the front end to rear end of the cargo hold and above the upper deck, with a section arranged with the fuel battery arranged evading the hazardous place on the deck.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a cargo ship equipped with a fuel cell.

Background Art

[0002] Conventionally, it has been proposed to mount a fuel cell on a ship and use all or part of the power generated by the fuel cell as propulsion power or as in-ship power. For example, Patent Document 1 discloses a liquefied gas carrier equipped with a power generation device using a fuel cell. In this liquefied gas carrier, boil-off gas generated in the cargo tank is reformed into fuel gas and then supplied to the anode of the fuel cell, and an oxidizing gas is supplied to the cathode of the fuel cell, and power generation is performed by the fuel cell. The generated power is supplied to the propulsion motor and the living quarters through a power distribution device.

[0003] In the liquefied gas carrier of Patent Document 1, the power generation device using a fuel cell is arranged on the exposed deck, and a part of the power generation device is above the cargo tank.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The interior of a cargo tank in which liquefied gas, heavy oil, etc. are stored is a compartment where a dangerous atmosphere continuously exists in the normal state. It is designated as a dangerous location, and various restrictions are imposed on the installation of electrical equipment, etc. to enhance safety. Although the compartment where the fuel cell is placed is not defined as a dangerous location, it is a compartment where there is a risk of generating an explosive mixture, so it is reasonable to handle it in accordance with the dangerous location. Since there are restrictions on the equipment installed in the compartment that becomes a dangerous location, it is desirable to keep the dangerous location as small as possible on the ship.

[0006] The present disclosure has been made in view of the above circumstances, and its object is to propose a structure for mounting a fuel cell while suppressing the expansion of a dangerous location in a cargo ship that transports cargo such as liquefied gas and heavy oil and in which a cargo hold becomes a dangerous location derived from the cargo.

Means for Solving the Problems

[0007] A cargo ship according to one aspect of the present disclosure has a hull provided with at least one cargo tank and a cargo hold that is a dangerous location derived from the cargo, and an engine room arranged behind the cargo hold, a propulsion electric motor arranged in the engine room, a hydrogen fuel tank for storing hydrogen fuel, a fuel cell power generation unit having a sealable casing and a fuel cell arranged in the casing that generates electricity using hydrogen supplied from the hydrogen fuel tank and oxygen in the air, and a power conversion device that supplies the power generated by the fuel cell power generation unit to at least one of the propulsion electric motor and the in-ship power load. When a region below a predetermined first height from a portion of the upper deck of the hull located above the cargo hold is defined as an on-deck dangerous location derived from the cargo, the hydrogen fuel tank is arranged in the hull between the front end and the rear end of the cargo hold. The fuel cell power generation unit is characterized in that, in a state where the fuel cell has retreated from the dangerous area on the deck, it is arranged above the upper deck and between the front end and the rear end of the cargo hold.

[0008] In the cargo ship with the above configuration, the compartment where the fuel cell is arranged, that is, the internal space of the casing, has retreated from the dangerous area on the deck. This means that the compartment where an explosive mixture may be generated in the fuel cell power generation unit does not overlap with the dangerous area on the deck derived from the cargo, ensuring safety. Furthermore, in the cargo ship with the above configuration, since the fuel cell power generation unit is arranged between the front end and the rear end of the cargo hold, the dangerous area derived from the fuel cell power generation unit is contained between the dangerous areas on the deck derived from the cargo hold. As a result, the fuel cell power generation unit can be arranged without the dangerous area expanding rearward, that is, toward the stern side.

Advantages of the Invention

[0009] According to the present disclosure, in a cargo ship where the cargo hold is a dangerous area derived from the cargo, a structure can be proposed that mounts a fuel cell while suppressing the expansion of the dangerous area.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying out the Invention

[0011] Next, embodiments of the present invention will be described with reference to the drawings.

[0012] 〔Schematic Configuration of Cargo Ship 1〕 FIG. 1 is a schematic side view showing the overall configuration of a cargo ship 1 according to an embodiment of the present disclosure. The cargo ship 1 shown in FIG. 1 includes a hull 11, a superstructure 20 provided on the hull 11, and a propeller 14 and a rudder 15 provided at the stern end of the hull 11. An engine room 13 is provided at the stern of the hull 11, and a cargo hold 12 is provided on the bow 17 side of the engine room 13 of the hull 11.

[0013] A propulsion motor 25 is disposed in the engine room 13. The propulsion motor 25 rotationally drives the propeller 14. Although the cargo ship 1 according to the present embodiment is an electric propulsion ship, the cargo ship 1 may be a hybrid propulsion ship equipped with a hybrid propulsion system combining a diesel engine, an electric motor, and a storage battery.

[0014] Above the engine room 13, a superstructure 20 protruding upward from the hull 11 is provided. The superstructure 20 is provided with a living area 2 and a bridge 3.

[0015] A cargo tank 16 is provided in the cargo hold 12. The cargo ship 1 according to the present embodiment is a liquefied gas carrier, and liquefied gas is stored in the cargo tank 16. Examples of the liquefied gas include liquefied hydrogen and LNG. However, the cargo is not limited to liquefied gas. For example, the cargo ship 1 may be an oil tanker, and heavy oil may be stored in the cargo tank 16. In FIG. 1, a rectangular cargo tank 16 is shown, but the shape of the cargo tank 16 is not limited to rectangular, and may be spherical, elliptical, or cylindrical with both ends closed by hemispheres (i.e., capsule type).

[0016] The cargo ship 1 is equipped with a hydrogen power generation system 6. The electric power generated by the hydrogen power generation system 6 is supplied to at least one of the propulsion motor 25 and the in-ship electric power load 26. The hydrogen power generation system 6 is composed of a fuel cell power generation unit 61, at least one hydrogen storage module 62, a power conversion device 63, and a storage battery 65.

[0017] Figure 2 is a block diagram showing the schematic configuration of the hydrogen power generation system 6. As shown in Figure 2, the hydrogen storage module 62 includes a hydrogen fuel tank 621 in which hydrogen fuel is stored and a tank valve 622 provided at the inlet and outlet of the hydrogen fuel tank 621. The hydrogen fuel is stored in the hydrogen fuel tank 621 as a gas or a liquid. The hydrogen fuel tank 621 is connected to the fuel cell power generation unit 61 via a pipe, and the hydrogen stored in the hydrogen fuel tank 621 is supplied to the fuel cell power generation unit 61 via the pipe. By opening and closing the tank valve 622, the supply / supply stop of hydrogen from the hydrogen fuel tank 621 to the fuel cell power generation unit 61 can be switched. The hydrogen storage module 62 may be configured to supply hydrogen to hydrogen utilization devices other than the hydrogen power generation system 6 mounted on the cargo ship 1. As such a hydrogen utilization device, a hydrogen boiler arranged in the engine room 13 is exemplified.

[0018] The fuel cell power generation unit 61 includes a fuel cell 611, a radiator 612, a high-pressure hydrogen facility 613, and a system control device 614, and is housed in a sealable casing 610. The casing 610 forms an enclosed compartment in which the fuel cell 611 is arranged.

[0019] The fuel cell 611 has a number of fuel cells, receives the supply of hydrogen, and causes an electrochemical reaction between the hydrogen and oxygen in the air to generate DC power. The radiator 612 regulates the temperature of the fuel cell 611 to a temperature suitable for power generation. For example, a cooling medium circulates between the radiator 612 and the fuel cell 611. The high-pressure hydrogen facility 613 adjusts the pressure of the hydrogen sent from the hydrogen storage module 62 and supplies it to the fuel cell 611. The system control device 614 is a device that controls the power generation of the fuel cell 611. The system control device 614 controls the high-pressure hydrogen facility 613 and the tank valve 622 so that hydrogen and oxygen are supplied to the fuel cell 611 such that power generation according to the load is performed. Further, the system control device 614 operates the radiator 612 so that an appropriate temperature of the fuel cell 611 is maintained. Further, the system control device 614 commands the power conversion device 63 to take out the power from the fuel cell 611.

[0020] The power conversion device 63 has a plurality of input systems and output systems, and converts and outputs the voltage, current, and frequency of the input power. For example, the system control device 614 calculates a command to the power conversion device 63 from the load state of the main switchboard 27 and the charge state of the storage battery 65. The power conversion device 63 takes out DC power from the fuel cell 611 according to the command from the system control device 614, converts (or adjusts) the voltage, etc. of the DC power, and sends it to the main switchboard 27. Power is supplied from the main switchboard 27 to the propulsion motor 25 via wiring. Further, power is supplied from the main switchboard 27 to the in-ship power load 26 via wiring. Here, the conversion of voltage, etc. may include at least one of DC-to-DC conversion, AC-to-DC conversion, DC-to-AC conversion, AC-to-AC conversion, voltage conversion, and power adjustment. Further, the power conversion device 63 stores the surplus of the generated power in the storage battery 65. The power stored in the storage battery 65 may be appropriately taken out by the power conversion device 63 and sent to the main switchboard 27.

[0021] 〔Arrangement of the hydrogen power generation system 6〕 Here, the arrangement of the hydrogen power generation system 6 on the cargo ship 1 will be described in detail. First, the above-deck dangerous area 100 and the cargo area 101 defined on the cargo ship 1 will be described. FIG. 3 is a diagram for explaining the above-deck dangerous area 100 and the cargo area 101 defined on the cargo ship 1.

[0022] As shown in FIG. 3, the upper deck 18 is an exposed deck covering the upper surface of the hull 11. An area within a predetermined first height X [m] or less from the portion of the upper deck 18 located above the cargo hold 12 is defined as the "above-deck dangerous area 100" derived from the cargo. More specifically, it is surrounded by a plane S1 parallel to the ship width direction Y [m] in front of the front end of the cargo hold 12 and a plane S2 parallel to the ship width direction Y [m] behind the rear end of the cargo hold 12, and the area within a first height X [m] or less from the upper deck 18 is defined as the above-deck dangerous area 100. However, when a part of the outer surface of the cargo tank 16 protrudes above the upper deck 18, the above-deck dangerous area 100 of the part where the cargo tank 16 protrudes is the area within a first height X [m] or less from the outer surface of the cargo tank 16. The above-deck dangerous area 100 is the area indicated by hatching in FIG. 3. X and Y are values determined by regulations and the like. For example, X = 2.4 and Y = 3 may be used.

[0023] An area surrounded by a plane S3 parallel to the ship width direction at the front end of the cargo hold 12 and a plane S4 parallel to the ship width direction at the rear end of the cargo hold 12 is defined as the "cargo area 101". The cargo area 101 is indicated by a thick two-dot chain line in FIG. 3. The cargo area 101 includes, in addition to the cargo hold 12 of the hull 11, the portion of the upper deck 18 corresponding to the area above the cargo hold 12 and the portion of the space above the upper deck 18 corresponding to the area above the cargo hold 12.

[0024] Returning to FIG. 1, the fuel cell power generation unit 61 is disposed above the upper deck 18 of the cargo area 101 in a state where the fuel cell 611 has substantially retreated from the dangerous area 100 on the deck. In the example shown in FIG. 1, in order to evacuate the entire fuel cell power generation unit 61 including the fuel cell 611 upward from the dangerous area 100 on the deck, the fuel cell power generation unit 61 is supported from below by at least one support column 71 erected on the upper deck 18. In other words, the fuel cell power generation unit 61 is placed on at least one support column 71 erected on the upper deck 18. The support column 71 has a second height H of the first height X [m] or more. Thereby, the fuel cell power generation unit 61 placed on the support column 71 is arranged at a position higher than the first height X from the upper deck 18. Since the fuel cell power generation unit 61 is arranged in front of the bridge 3, it is desirable that the second height H is as small as possible while being equal to or greater than the first height X [m] so that the view from the bridge 3 is not blocked by the fuel cell power generation unit 61.

[0025] In order to make the space between the fuel cell power generation unit 61 and the upper deck 18 open, when there are a plurality of support columns 71, the spaces between the plurality of support columns 71 are open. In other words, the plurality of support columns 71 are horizontally separated from each other to such an extent that crew members can pass through. Moreover, the vertical space between the upper deck 18 and the fuel cell power generation unit 61 separated by the support column 71 is a height through which crew members wearing safety shoes and helmets can sufficiently pass. Thereby, visibility and trafficability on the upper deck 18 are ensured below the fuel cell power generation unit 61, and crew members can pass below the fuel cell power generation unit 61 or perform work below the fuel cell power generation unit 61. Note that the configuration of the support column 71 is not limited to the above, and it may be in a block shape provided with a passage tunnel or in a frame shape without a wall.

[0026] The hydrogen storage module 62 is arranged in the cargo area 101. In the example shown in FIG. 1, the hydrogen storage module 62 is arranged on the bow 17 side of the fuel cell power generation unit 61. Among the hydrogen storage module 62, the lower part of the hydrogen fuel tank 621 is below the upper deck 18, and the upper part protrudes upward from the upper deck 18. By adopting such an embodiment in which a part of the hydrogen fuel tank 621 is embedded in the upper deck 18, while ensuring a volume capable of accommodating the amount of hydrogen required for navigation in the hydrogen fuel tank 621, the protruding height of the hydrogen fuel tank 621 from the upper deck 18 can be suppressed, and the forward view from the bridge 3 can be ensured.

[0027] The power conversion device 63 and the storage battery 65 are arranged in the engine room 13. However, the power conversion device 63 may be arranged in the residential area 2. Alternatively, the power conversion device 63 may be arranged in the casing 610 of the fuel cell power generation unit 61. When the power conversion device 63 is arranged in the casing 610, two independent spaces are formed in the casing 610, and the power conversion device 63 may be accommodated in one of the two spaces, and the fuel cell power generation unit 61 may be accommodated in the other.

[0028] As described above, the cargo ship 1 according to the present disclosure has a hull 11 provided with at least one cargo tank 16, a cargo hold 12 which is a dangerous location derived from the cargo, and an engine room 13 arranged behind the cargo hold 12. A propulsion motor 25 arranged in the engine room 13. A hydrogen fuel tank 621 for storing hydrogen fuel. A hermetically sealable casing 610, and a fuel cell power generation unit 61 having a fuel cell 611 arranged in the casing 610 and generating power using hydrogen supplied from the hydrogen fuel tank 621 and oxygen in the air. It includes a power conversion device 63 for supplying the power generated by the fuel cell power generation unit 61 to at least one of the propulsion motor 25 and the in-ship power load 26. When a region below a predetermined first height X from the portion of the upper deck 18 of the hull 11 located above the cargo hold 12 is defined as the on-deck dangerous location 100 derived from the cargo. The hydrogen fuel tank 621 is disposed longitudinally in the hull 11 between the front end and the rear end of the cargo hold 12. The fuel cell power generation unit 61 is characterized in that, in a state where the compartment in which the fuel cell 611 is disposed is retracted from the on-deck dangerous area 100, it is disposed longitudinally between the front end and the rear end of the cargo hold 12 and above the upper deck 18.

[0029] In the cargo ship 1 having the above configuration, the compartment in which the fuel cell 611 is disposed, that is, the internal space of the casing 610, is retracted from the on-deck dangerous area 100. This means that the compartment in which an explosive mixture may be generated in the fuel cell power generation unit 61 does not overlap with the on-deck dangerous area 100 derived from the cargo, ensuring safety. Further, in the cargo ship 1 having the above configuration, since the fuel cell power generation unit 61 is disposed longitudinally between the front end and the rear end of the cargo hold 12 (i.e., the cargo area 101), the dangerous area derived from the fuel cell power generation unit 61 is contained within the longitudinal range of the on-deck dangerous area 100 derived from the cargo hold 12. Thereby, the fuel cell power generation unit 61 can be disposed without the dangerous area including the on-deck dangerous area 100 expanding rearward, i.e., toward the stern side. Since the dangerous area does not expand toward the stern side where the superstructure 20 is located, safety measures such as installing a partition to expand the dangerous area to an existing non-dangerous compartment and reviewing peripheral equipment are not required.

[0030] In the cargo ship 1 according to the present embodiment, the fuel cell power generation unit 61 is supported from below by at least one support column 71 erected on the upper deck 18, and the support column 71 has a second height H higher than the first height X.

[0031] Since the entire fuel cell power generation unit 61 is thus retracted upward from the on-deck dangerous area 100, even if hydrogen leaks from the fuel cell power generation unit 61, hydrogen, which is lighter than air, rises without floating on the upper deck 18, thus reducing the possibility of ignition near crew members passing on the upper deck 18.

[0032] In the cargo ship 1 described above, when there are a plurality of support columns 71 so that passage is possible between the upper deck 18 and the fuel cell power generation unit 61 vertically, it is desirable that the space between the plurality of support columns 71 is open. By having the space between the plurality of support columns 71 open in this way, traffic and visibility are ensured even if the support columns 71 are provided on the upper deck 18.

[0033] Also, in the cargo ship 1 according to the present embodiment, the lower part of the hydrogen fuel tank 621 is below the upper deck 18, and the upper part of the hydrogen fuel tank 621 protrudes upward from the upper deck 18.

[0034] In this way, the hydrogen fuel tank 621 is installed in such a manner that its lower part is embedded in the upper deck 18, so that while ensuring a sufficient tank capacity, the amount of protrusion upward from the upper deck 18 is suppressed, and a forward view from the bridge 3 can be ensured.

[0035] Although the preferred embodiments have been disclosed above, within the scope not departing from the gist of the present invention, those obtained by changing the details of the specific structure and / or function of the above embodiments may also be included in the present invention. The configuration of the cargo ship 1 described above can be changed, for example, as in the modification examples described below. Although a plurality of modification examples will be described below, combinations of the features shown in one or more of the modification examples may also be applied to the above embodiments.

[0036] [Modification Example 1] FIG. 4 is a schematic side view showing the overall configuration of the cargo ship 1 according to Modification Example 1. As shown in FIG. 4, the hydrogen power generation system 6A mounted on the cargo ship 1 according to Modification Example 1 is different from the hydrogen power generation system 6 according to the above-described embodiment in that the fuel cell power generation unit 61 is arranged in the cargo area 101 within a range of a first height X or less from the upper deck 18.

[0037] In the hydrogen power generation system 6A, the casing 610a of the fuel cell power generation unit 61 is placed directly on the upper deck 18 or via a jig so that at least a part thereof overlaps with the dangerous area 100 on the deck. In the hydrogen power generation system 6A, the casing 610a of the fuel cell power generation unit 61 is provided with an airlock. Specifically, the casing 610a includes multiple containers including an inner container and an outer container, and airtight doors provided on each of the multiple containers. Here, the plurality of airtight doors are configured not to open simultaneously. In the casing 610a provided with an airlock in this way, gas cannot directly enter from outside the casing 610a into it, nor can gas directly exit from inside the casing 610a to the outside. Therefore, although the casing 610a is arranged in the dangerous area 100 on the deck, the compartment where the fuel cell 611 formed inside the casing 610a is arranged becomes a space with an atmosphere independent from the dangerous area 100 on the deck. That is to say, in the hydrogen power generation system 6A, it can be said that the compartment where the fuel cell 611 is arranged is substantially withdrawn from the dangerous area 100 on the deck.

[0038] 〔Modification Example 2〕 FIG. 5 is a schematic side view showing the overall configuration of the cargo ship 1 according to Modification Example 2. As shown in FIG. 5, the hydrogen power generation system 6B mounted on the cargo ship 1 according to Modification Example 2 is different from the hydrogen power generation system 6 according to the aforementioned embodiment in that the hydrogen storage module 62 is arranged above the upper deck 18 in the cargo area 101. More specifically, in the hydrogen power generation system 6B, the hydrogen fuel tank 621 of the hydrogen storage module 62 is supported by the upper deck 18 via a support tool 72.

[0039] In the cargo ship 1 according to Modification Example 2, the capacity of the hydrogen fuel tank 621 is restricted so that the forward view from the bridge 3 is not blocked by the hydrogen fuel tank 621. In this case, in order to eliminate the shortage of hydrogen fuel, as described in the following Modification Example 3, the boil-off gas of the cargo tank 16 may be replenished to the hydrogen fuel tank 621 as fuel.

[0040] 〔Modification Example 3〕 FIG. 6 is a schematic side view showing the overall configuration of the cargo ship 1 according to Modification 6. As shown in FIG. 6, the hydrogen power generation system 6C mounted on the cargo ship 1 according to Modification 3 is different from the hydrogen power generation system 6 according to the above-described embodiment in that the cargo tank 16 and the hydrogen fuel tank 621 are connected by a pipe for feeding boil-off gas in the cargo tank 16 to the hydrogen fuel tank 621.

[0041] In the hydrogen power generation system 6C, a branch pipe 42 of the boil-off gas pipe 41 connected to the cargo tank 16 is connected to the hydrogen fuel tank 621 of the hydrogen storage module 62. The branch pipe 42 is provided with an on-off valve 43 and a compressor 44. With this configuration, the boil-off gas from the cargo tank 16 is compressed by the compressor 44 and then fed to the hydrogen fuel tank 621 to fill the hydrogen fuel tank 621. When the liquefied gas stored in the cargo tank 16 is liquefied hydrogen, hydrogen gas as boil-off gas is sent to the hydrogen fuel tank 621. When the liquefied gas stored in the cargo tank 16 is LNG, a reformer is provided in the branch pipe 42, and the boil-off gas is reformed into hydrogen gas by the reformer and then sent to the hydrogen fuel tank 621. In the hydrogen power generation system 6C, it is possible to switch between replenishing fuel from onshore or offshore fuel supply facilities to the hydrogen fuel tank 621 and replenishing fuel from the cargo tank 16 to the hydrogen fuel tank 621.

Description of Reference Numerals

[0042] 1: Cargo ship 6, 6A - 6C: Hydrogen power generation system 11: Hull 12: Cargo hold 13: Engine room 16: Cargo tank 18: Upper deck 25: Propulsion motor 26: Onboard power load 27: Main switchboard 61: Fuel cell power generation unit 63: Power conversion device 71: Support column 100: Hazardous area on deck 101: Cargo area 610, 610a: Casing 611: Fuel cell 621: Hydrogen fuel tank

Claims

1. A hull having at least one cargo tank, a cargo hold which is a dangerous location derived from cargo, and an engine room arranged behind the cargo hold; A propulsion electric motor arranged in the engine room; A hydrogen fuel tank for storing hydrogen fuel; A fuel cell power generation unit having a sealable casing and a fuel cell arranged inside the casing for generating electricity using hydrogen supplied from the hydrogen fuel tank and oxygen in the air; A power conversion device for supplying the power generated by the fuel cell power generation unit to at least one of the propulsion electric motor and the in-ship power load; When a region below a predetermined first height from a portion of the upper deck of the hull located above the cargo hold is defined as an on-deck dangerous location derived from cargo, The hydrogen fuel tank is arranged in the hull between the front end and the rear end of the cargo hold; The fuel cell power generation unit is arranged between the front end and the rear end of the cargo hold and above the upper deck in a state where the compartment in which the fuel cell is arranged has retreated from the on-deck dangerous location. A cargo carrier.

2. The casing is supported from below by at least one support column erected on the upper deck, and the support column has a second height higher than the first height. The cargo carrier according to Claim 1.

3. A plurality of the support columns are provided, and the space between the support columns is open. The cargo carrier according to Claim 2.

4. The casing has an airlock composed of multiple containers and airtight doors provided on each of the multiple containers. At least a part of the casing is arranged so as to overlap with the on-deck dangerous location. The cargo carrier according to Claim 1.

5. The lower part of the hydrogen fuel tank is below the upper deck, and the upper part of the hydrogen fuel tank protrudes upward from the upper deck. The cargo carrier according to any one of Claims 1 to 4.

6. The cargo tank and the hydrogen fuel tank are connected by a pipe for feeding boil-off gas in the cargo tank to the hydrogen fuel tank. The cargo carrier according to any one of Claims 1 to 5.

Images