KR102605416B1 - cryogenic fuel tank - Google Patents

Abstract

The present invention relates to a cryogenic fuel tank (10), comprising a metrology arrangement (30) for measuring and/or recording one or more physical quantities of fuel within the fuel tank (10), wherein the fuel tank (10) has an inner shell. (16) and an outer shell (18), the inner shell (16) comprising a first cylindrical shell portion (16.1) and end portions (16.2) at both ends thereof, and the outer shell (18) comprising a first cylindrical shell portion (16.1) and end portions (16.2) at both ends thereof. 2 comprising a cylindrical shell portion 18.1 and end portions 18.2 at both ends thereof, comprising an insulating cavity 20 between the inner shell 16 and the outer shell 18, and a cryogenic fuel tank 10. ) further includes a tank connection space (22). The metering arrangement (30) includes an instrument guide pipe (32) for a measurement system (34) of one or more physical quantities of fuel in the fuel tank (10), and a measurement system (34) coupled to the instrument guide pipe (32). and the appliance guide pipe 32 is arranged to extend from the tank connection space 22 to the tank space 11 through the insulating cavity 20.

Description

cryogenic fuel tank

The present invention relates to a cryogenic fuel tank, the fuel tank comprising an instrumentation arrangement for measuring and/or recording one or more physical quantities of the fuel within the fuel tank, the fuel tank comprising an inner shell and an outer shell. and the inner shell includes a first cylindrical shell portion and end portions at both ends thereof, the outer shell includes a second cylindrical shell portion and end portions at both ends thereof, and the fuel tank includes the inner shell and the outer shell. Includes an insulating cavity between

The present invention relates to the field of storing liquefied gases at cryogenic conditions in pressure-proof tanks for use in gas consumers and to the instrumentation of the tanks in a suitable manner. By these measurements, it is possible to measure and/or record the physical amount of gas in the tank. One of the quantities of most interest is the amount of gas in the liquid phase, but it may be desirable to measure other quantities as well.

Radar level instruments are known to measure the distance from a transmitter/sensor to the surface of a liquid located further down in much the same way as an ultrasonic level sensor, by measuring the time of flight of the traveling wave and then determining the level of the process material. there is. They are considered continuous level measurement devices because they continue to measure level even as the level of the liquid in the container changes. The basic difference between radar level instruments and ultrasonic level instruments is the type of wave used. Radar level devices use radio waves instead of sound waves used in ultrasonic devices. Radio waves are electromagnetic in nature and have very high frequencies in the microwave frequency range.

There are two basic types of radar level devices: guided wave radar and non-contacting wave radar. Guided wave radar devices use radio-guided probes to guide radio waves into the process liquid, while non-contact radar devices send radio waves through an open space and bounce them off the process material.

Utility model CN207379583U discloses a non-contact radar level gauge system for checking the level of packing material of articles in a storage tank.

Utility model CN206504772U discloses a radar level meter system provided with a mounting pipe and a radar level gauge mounted on the mounting pipe. The mounting pipe has a float so that radar waves reflect off the float, improving measurement accuracy. The distance between the liquid level and the radar level gauge is equal to the reading of the radar level gauge and the thickness of the float. When the liquid level is high, the float is pulled below the liquid level so the float does not collide with the radar antenna.

Since the present invention relates to fuel tanks, operational safety is a very important aspect in handling highly flammable fuels, and in this connection the use of double wall arrangements of liquefied gas tanks is known.

Publication WO2017042424A1 shows an LNG-fuel tank comprising an inner shell of stainless steel, an outer shell and a cavity 20 with an insulator between them. WO2017042424A1 discloses a method for determining fuel level in a tank using a radar-based detector. To this end, the LNG fuel tank is provided with a manhole structure in the cylindrical shell portion of the tank to allow access to the interior of the LNG fuel tank. The manhole provides a means for determining the fuel level within the inner shell of the tank. This type of arrangement requires lead-through of the wiring through the outer shell, a potential hazard that could compromise the tank's tightness.

The object of the present invention is to provide a cryogenic fuel tank from which measurements can be obtained reliably and easily.

The object of the invention can be achieved substantially as set forth in the independent claims and other claims setting forth more details of different embodiments of the invention.

According to one embodiment of the invention, a cryogenic fuel tank includes a metrology arrangement for measuring and/or recording one or more physical quantities of the fuel within the fuel tank, the fuel tank comprising an inner shell, an outer shell, and an inner shell includes a first cylindrical shell portion and end portions at both ends, the outer shell includes a second cylindrical shell portion and end portions at both ends, and the cryogenic fuel tank has an insulating cavity between the inner shell and the outer shell. Includes. The cryogenic fuel tank further includes a tank connection space. The metrology arrangement includes an instrument guide pipe and a radar-based liquid level measurement system configured to measure the liquid level of fuel in the fuel tank, the measurement system being coupled to the instrument guide pipe. The appliance guide pipe is arranged to extend through the insulating cavity from the tank connection space to the tank space.

The tank connection space is a space for accommodating an end of the device guide pipe and a measurement system coupled to the device guide pipe. The tank connection space is arranged gas-tight but accessible, for example for maintenance.

According to one embodiment of the invention, the appliance guide pipe is arranged to extend through the end portion of the outer shell into the insulating cavity, and the appliance guide pipe extends from the insulating cavity through the first cylindrical portion of the inner shell of the fuel tank into the tank space. It is arranged to extend further.

According to one embodiment of the invention, the first section of the appliance guide pipe is arranged to extend through the end portion of the outer shell and the second section of the appliance guide pipe is arranged to extend through the end portion of the inner shell and the end portion of the inner shell. arranged to extend along the insulating cavity between the end portions of the outer shell into the insulating cavity between the first cylindrical portion and the second cylindrical portion, and further, a third section of the appliance guide pipe connected to the cryogenic fuel tank. arranged to extend longitudinally into the insulating cavity between the first cylindrical portion and the second cylindrical portion, and the fourth section of the appliance guide pipe is arranged to extend through the inner shell of the fuel tank into the tank space. do.

According to one embodiment of the invention, a cryogenic fuel tank includes a metrology arrangement for measuring and/or recording one or more physical quantities of the fuel within the fuel tank, the fuel tank comprising an inner shell, an outer shell, and an inner shell includes a first cylindrical shell portion and end portions at both ends, the outer shell includes a second cylindrical shell portion and end portions at both ends, and the cryogenic fuel tank has an insulating cavity between the inner shell and the outer shell. wherein the measurement arrangement includes a measuring system configured to measure and/or record one or more physical quantities of the fuel in the fuel tank and an instrument guide pipe, the measurement system being coupled to the instrument guide pipe, the instrument guide pipe being insulated. It is arranged to extend from the tank connection space to the tank space through the cavity.

According to one embodiment of the invention, the appliance guide pipe portion in the tank space includes an opening in the external wall.

According to one embodiment of the invention, the first cylindrical shell part is provided with a lead through, through which a fourth section of the instrument guide pipe is arranged to extend into the tank space, and a fourth section of the instrument guide pipe extends from the lead through. It is arranged to extend radially towards the center of the first cylindrical shell portion and also towards the first shell wall radially opposite to the lead through.

According to one embodiment of the invention, the fourth section of the instrument guide pipe includes an opening in its outer wall.

According to one embodiment of the invention, the lead through includes a radially inwardly extending cup having a rim attached to the inner shell, and the instrument guide pipe is guided through a bottom portion of the cup.

According to one embodiment of the invention, the metrology arrangement comprises a radar-based measurement system, and the fourth section of the instrument guide pipe comprises a float portion arranged to reflect radar signals.

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According to one embodiment of the invention, the measurement arrangement comprises an inertial measurement unit for defining the angle of inclination of the fuel tank.

According to one embodiment of the invention, a cryogenic fuel tank is provided with two separate metering arrangements, the metering arrangement comprising a temperature measurement system and a radar-based liquid level measurement system.

According to one embodiment of the invention, the metrology arrangement comprises a radar-based measurement system and the fourth section of the instrument guide pipe comprises a static reference reflector in the pipe.

The exemplary embodiments of the invention provided in this patent application should not be construed to limit the applicability of the appended claims. The verb “comprising” is also used in this patent application as an open limitation so as not to exclude the presence of unrecited features. Features recited in dependent claims may be freely combined with each other unless explicitly stated otherwise. New features contemplated as features of the invention are particularly disclosed in the appended claims.

Next, the present invention will be explained with reference to the accompanying exemplary and schematic drawings.

1 shows a cryogenic fuel tank according to an embodiment of the present invention;
FIG. 2 is a diagram illustrating lines II-II of FIG. 1 according to an embodiment of the present invention;
Figure 3 is a diagram showing lines II-II of Figure 1 according to another embodiment of the present invention;
4 shows another embodiment of the present invention,
5 shows another embodiment of the present invention,
5 shows another embodiment of the present invention,
6 shows a cryogenic fuel tank;
Figure 7 shows the cryogenic fuel tank according to Figure 6 in the service phase.

Figure 1 shows a cryogenic fuel tank 10 arranged on a marine deck 12, and Figure 2 shows lines II-II of Figure 1 according to an embodiment of the present invention. The cryogenic fuel tank can serve, for example, as a liquefied natural gas fuel tank according to a preferred embodiment of the present invention. The cryogenic fuel tank (10) is supported by saddles (14) on the deck (12). The cryogenic fuel tank 10 includes an inner shell 16 made of stainless steel to withstand conditions within the tank. The tank space 11 in the inner shell forms a fuel storage space. The cryogenic fuel tank 10 also includes an outer shell 18 made of stainless steel. The inner shell 16 comprises a first cylindrical shell part 16.1 with a first longitudinal central axis A1 and end parts 16.2 at both ends thereof, and the outer shell 18 has a second type It comprises a second cylindrical shell part 18.1 with a directional central axis A2 and respective end parts 18.2 at both ends thereof. In Figure 1 the first and second longitudinal axes coincide with each other, but this is only an optional feature. The longitudinal axes are parallel to the deck 12, i.e. oriented substantially horizontally. There is an insulating cavity 20 between the inner shell 16 and the outer shell 18 surrounding the inner shell. The insulating cavity 20 may be filled with a suitable insulating material or, as in the case of Figure 1, may be a vacuum insulating space. The inner shell 16 is supported on or against the outer shell 18 by supports arranged in the cavity 20 . The end portions 16.2 and 18.2 are preferably dome-shaped and the inner and outer shells are configured to maintain a pressure of more than 500 kPa.

The cryogenic fuel tank 10 as shown in FIG. 1 is welded to the outer shell 18 of the tank 10 forming a safety barrier against inadvertent gas leakage, or has several gas-tight connections arranged therewith. The room or space (22) is provided by other suitable means. This space 22 may be referred to as a tank connection space and houses, for example, piping and equipment required for filling or emptying the fuel tank 10, not shown here. The tank connection space 22 is arranged to connect with the end portion of the cryogenic tank 10.

The cryogenic tank (10) according to the invention comprises a metrology arrangement (30) for measuring and/or recording one or more physical quantities of the fuel in the cryogenic fuel tank (10). The metering arrangement 30 includes a measuring system 34 for measuring one or more physical quantities of fuel in a fuel tank and an instrument guide pipe 32 for use by the measuring system 34 . The appliance guide pipe 32 is arranged to extend from the tank connection space 22 through the insulating cavity 20 into the tank space 11 and substantially extends into the tank space 11 within the first cylindrical shell portion 16.1. It traverses from wall to wall. The measurement system 34 comprises an interface for measurement signal(s) and control within the tank connection space 22.

Tank connection space 22 is typically a gas-tight enclosure containing all tank connections, fittings, flanges and tank valves. It is constructed of cryogenic heat-resistant material and has a bilge well with a high-level indicator and a low-temperature sensor. The tank connection space (TCS) is normally inaccessible and cannot be entered by personnel unless it is confirmed that there is sufficient oxygen and the absence of an explosive atmosphere. For safety reasons, the TCS is advantageously provided with permanent gas detection, fixed fire detection and mechanical forced ventilation, which changes the air at least 30 times/hour.

The instrument guide pipe 32 of Figure 1 generally includes four sections. The first section 32.1, which can also be referred to as the first end of the instrument guide pipe 32, extends in the longitudinal direction of the cryogenic fuel tank 10 generally parallel to the longitudinal central axes A1, A2, into a tank connection space ( 22) through the end portions 18.2 of the outer shell 18. The first section 32.1 has its ends in the gas tight tank connection space 22, which increases the safety of the cryogenic fuel tank 10. The second section 32.2 is arranged to extend at least radially along the insulating cavity 20 between the end part 16.2 of the inner shell 16 and the end part 18.2 of the outer shell 18. The second section 32.2 runs towards the radial periphery of the outer shell 18, but the position of the first section 32.1 need not necessarily coincide with the second longitudinal central axis A2, and/or Since one section is not necessarily a straight pipe as shown in Figures 1 and 2, the direction does not have to be exactly radial or straight. Accordingly, the second section may also be slightly curved. Figure 1 also shows that the second section 32.2 has a longitudinal component. The third section 32.3 of the appliance guide pipe 32 is arranged to extend generally longitudinally along the insulating cavity 20 between the inner shell 16 and the outer shell 18 over a predetermined distance. The fourth section 32.4 of the instrument guide pipe 32 is arranged to extend into the fuel tank in a substantially radial direction. The fourth section 32.4 of the appliance guide pipe 32 preferably extends from wall to wall through the tank space 11. The fourth section 32.4 and the third section 32.3 are advantageously substantially perpendicular to each other. The first, second, third and fourth sections are arranged to provide compensation for any thermal expansion of the instrument guide pipe 32, inner shell 16 and/or outer shell 18. The machine guide pipe 32 includes an angle portion between the first, second, third and fourth sections, so that the machine guide pipe 32 moves with the inner and outer shells relative to each other due to temperature changes. Bending without damage.

3 shows two separate measurement arrangements in the cryogenic fuel tank 10 for measuring at least two different physical quantities of the fuel in the cryogenic fuel tank 10, with a dedicated instrument guide pipe 32 for each measurement system. (30) shows drawings II-II in Fig. 1 according to another embodiment of the present invention where provided.

The measurement system 34 coupled to the first end of the instrument guide pipe 32 in the embodiment of Figure 1 is a radar-based liquid level measurement system 34 or a liquid level indicator. In this embodiment, instrument guide pipe 32 is a waveguide through which radar waves are transmitted from radar-based liquid level measurement system 34 and through which waves reflected from the liquid surface are transmitted back to radar-based liquid level measurement system 34. Therefore, the guide pipe 32 serves to guide radar waves into the pipe. Although not shown in the drawing, the radar-based liquid level measurement system 34 may be equipped with an integrated shut-off valve to provide the possibility to easily remove the radar device if maintenance is required even while the tank is in operation. Radar-based liquid level measurement system 34 may also have an integrated pressure transmitter that measures the pressure in the gas phase of tank 10.

Figure 4 shows a feature relating to the fourth section 32.4 of the appliance pipe, in which the pipe is provided with several openings 36 through the wall of the pipe. That is, the appliance guide pipe portion within the tank space 11 includes an opening 36 in its outer wall. The openings 36 are distributed substantially uniformly over the length of the fourth section. This provides the effect of allowing gaseous gas to flow into or out of the pipe when the horizontal level of the liquefied fuel gas in the cryogenic fuel tank rises or falls. Equalizing the pressure inside and outside the instrument guide pipe 32 allows the liquid surface level inside the fourth section of the guide pipe 32.4 to follow the liquid surface level within the tank. By appropriately dimensioning the opening 36, sudden changes in surface level within the pipe can also be prevented.

Although this is advantageous, the fourth section 32.4 does not necessarily have to be arranged in the direction normal to the liquid surface in the tank. If there is an angle between the normal to the liquid surface and the fourth section (32.4) of the appliance piping, the actual position of the liquid level can be calculated based on the angle and dimensions of the tank. Additionally, when a cryogenic fuel tank is installed on a ship, it naturally changes its inclination angle along with the ship, which results in a short-term or long-term inclination of the liquid surface with respect to the longitudinal central axis A1 of the inner shell. According to one embodiment of the invention, the cryogenic fuel tank advantageously comprises an inertial measurement unit (IMU) 38 mounted in the tank connection space 22. The IMU uses a 3-axis gyroscope, 3-axis accelerometer, and 3-axis magnetometer to provide accurate angle and orientation information of the fuel tank unit 10. The distance from the fourth section 32.4 to the longitudinal center of the tank in combination with the angle of the tank can be used to calculate the actual liquid level in the tank, as the measurement system 34 uses the information from the inertial measurement unit 38. This is because it is configured to be used.

Figure 4 also shows another embodiment of the invention in which the metrology arrangement 30 comprises a float portion 40 slidably disposed within the pipe in the fourth section 32.4 of the instrument guide pipe 30. . The float portion 40 has a surface that facilitates reflection of radar signals from the float portion. The surface is advantageously perpendicular to the longitudinal direction of the fourth section 32.4 of the instrument guide pipe 30 . The surface of the float portion 40 may be metal, for example. In this way, since, for example, the dielectric constant of liquefied natural gas is rather low (1.7 for methane), the liquid surface will result in weak reflections, and by the floating part, the sensitivity of the radar measurement will be improved, providing a clear view of the liquid surface. An indication can be provided. The float portion 40 is advantageously configured to float such that its upper surface is near the surface of the liquid. The fourth section 32.4 and the float portion of the instrument guide pipe 30 are configured so that the float portion 40 can always move by floating with the liquid level from one end of the fourth section to the other end.

Figure 5 discloses two further aspects of the invention. The embodiment of the invention shown in Figure 5 includes a static reference reflector 42 arranged within the fourth section 32.4 of the instrument guide pipe 32 for optional use with a radar-based liquid level measurement system. The reference reflector 42 may for example be a fin arranged to extend radially into the pipe 32 . In Figure 5, fin 42 extends only partially into the pipe, providing the necessary reflection effect for the radar system to identify the reference reflector. The reference reflector 42 can also be obtained by a suitable internal extension in the instrument guide pipe 32, which can for example be an orifice or a pin leading through the pipe. Because the reference reflector is in a fixed position, this results in a reference signal for the radar to provide accurate liquid level measurements. Since the inner shell can move relative to the outer shell and the pipe can be bent at least to some extent, interference with the reflection time of the radar wave can occur. By means of a static reference reflector 42 the interference can be compensated. A static reference reflector 42 , such as a fin, is advantageously assembled inside the guide pipe 32 at a position where the guide pipe extends through the inner shell 16 . Reference reflector 42 will always provide a small reflection, which can be used as a reference by the radar to increase accuracy.

Instead of a radar-based measurement system, the measurement system 34 coupled to the instrument guide pipe 32 may be an ultrasonic liquid level measurement system 34. An ultrasonic liquid level measurement system may be used in conjunction with the instrument guide pipe 32 similar to a radar based liquid level measurement system. A reference reflector mounted inside pipe 32 can be used to continuously calibrate the sensor to compensate for changes in the speed of sound waves as the temperature changes. Ultrasonic devices can also be used to indirectly measure the temperature in a gas.

Figure 5 shows another embodiment of the present invention. The first cylindrical part 16.1 of the inner shell 16 can be provided with a special lead through 44 for optional use in connection with the instrument guide pipe 32. The lead through (44) includes a radially inwardly extending cup (45) with a rim (46) attached to the inner shell (16.1) of the cryogenic fuel tank (10). The instrument guide pipe 32 is guided through the bottom part of the cup. The cup is positioned between the fourth section (32.4) and the third section (32.2) with the fourth section (32.4) penetrating the cup perpendicular to the third section of the appliance guide pipe (32.3) running along the insulating cavity (20). It has a suitably selected depth and diameter so that it is possible to arrange a larger bending radius of the angular portion.

Figures 6 and 7 show a measurement system 34 coupled to the first end of the instrument guide pipe 32, which is a temperature measurement system 34'. The temperature measurement system includes a flexible probe portion and has several probe elements at different positions on the probe. In this way, the flexible probe can be inserted into the instrument guide pipe 32 and also removed. In Figure 6 the flexible probe is fully inserted into the guide pipe 32, and in Figure 7 the probe is partially removed, for example for servicing or replacement of the probe. If insertion of the probe within the tube is too difficult, a steel wire looping the end of the pipe 32 therein may be used to pull the probe within the pipe instead of pushing it. Temperature measurement system 34' can be used concurrently with the liquid level measurement system in the embodiment illustrated in FIG. 3.

According to an embodiment of the invention which otherwise corresponds to that shown in the other figures, the tank connection space is separate from the cryogenic tank, i.e. not integral therewith. The instrument guide pipe extends through the end portions of the outer shell and through the barrier channel into the tank connection space. The instrument guide pipe is surrounded in a gas-tight manner by a barrier channel between the end portion of the outer shell and the tank connection space. The barrier channel may, for example, be a pipe with a larger diameter than the diameter of the instrument guide pipe.

Although the invention is described herein by way of example and in connection with what is considered the most preferred embodiment, the invention is not limited to the disclosed embodiments but rather includes features thereof included within the scope of the invention as defined in the appended claims. It should be understood that it is intended to encompass various combinations or variations and several other applications. Details and technical features mentioned in connection with any of the embodiments above may be used in connection with any other embodiment when such combination is technically feasible.

Claims (14)

A cryogenic fuel tank (10) comprising an instrumentation arrangement (30) for measuring and/or recording one or more physical quantities of the fuel within the cryogenic fuel tank (10), comprising:
The cryogenic fuel tank (10) includes an inner shell (16) and an outer shell (18),
The inner shell (16) comprises a first cylindrical shell part (16.1) and end parts (16.2) at both ends,
The outer shell (18) comprises a second cylindrical shell part (18.1) and end parts (18.2) at both ends,
The cryogenic fuel tank (10) includes an insulating cavity (20) between the inner shell (16) and the outer shell (18),
The cryogenic fuel tank (10) further includes a tank connection space (22),
The metering arrangement (30) includes an instrument guide pipe (32) and a radar-based liquid measurement system configured to measure the liquid level of the fuel in the cryogenic fuel tank (10) coupled to the instrument guide pipe (32) 34), wherein the equipment guide pipe 32 is a waveguide through which radar waves are transmitted along the equipment guide pipe 32, and also the insulating cavity from the tank connection space 22 to the tank space 11. A cryogenic fuel tank (10) arranged to extend through (20). According to claim 1,
The appliance guide pipe 32 passes the cryogenic fuel through the end part 18.2 of the outer shell 18 into the insulating cavity 20 and further from the insulating cavity 20 into the tank space 11. A cryogenic fuel tank (10) arranged to extend through the first cylindrical shell portion (16.1) of the inner shell (16) of the tank (10). According to claim 1,
a first section (32.1) of the instrument guide pipe (32) is arranged to extend through the end portion (18.2) of the outer shell (18),
The second section 32.2 of the appliance guide pipe 32 forms an insulating cavity 20 between the end portion 16.2 of the inner shell 16 and the end portion 18.2 of the outer shell 18. arranged to extend into the insulating cavity (20) between the first cylindrical shell part (16.1) and the second cylindrical shell part (18.1),
Additionally, the third section 32.3 of the appliance guide pipe is positioned in the insulating cavity between the first cylindrical shell portion 16.1 and the second cylindrical shell portion 18.1 in the longitudinal direction of the cryogenic fuel tank 10. (20) arranged to extend into the
The fourth section (32.4) of the appliance guide pipe (32) is arranged to extend through the inner shell (16) of the cryogenic fuel tank (10) into the tank space (11). According to claim 3,
The first section (32.1) of the instrument guide pipe (32) is arranged to extend through the end portion (18.2) of the outer shell (18) in the longitudinal direction of the cryogenic fuel tank (10). (10). According to claim 3,
Cryogenic fuel tank, characterized in that the first cylindrical shell part (16.1) is provided with a lead through (44) arranged so that the fourth section (32.4) of the instrument guide pipe (32) extends into the tank space (11). (10). According to claim 5,
The fourth section 32.4 of the instrument guide pipe 32 extends radially from the lead through 44 towards the center of the first cylindrical shell part 16.1 and further extends radially to the lead through 44. Cryogenic fuel tank (10), characterized in that the first cylindrical shell portion (16.1) opposite to is arranged to extend towards the wall. According to claim 3,
Cryogenic fuel tank (10), wherein the fourth section (32.4) of the instrument guide pipe (32) in the tank space (11) comprises openings (36) in the external wall. According to claim 3,
The cryogenic fuel tank (10), wherein the fourth section (32.4) of the instrument guide pipe (32) comprises openings (36) in the outer wall. According to claim 5,
The lead through (44) includes a radially inwardly extending cup (45) with a rim (46) attached to the inner shell (16), and the instrument guide pipe (32) extends at the bottom of the cup (45). Guided through section, cryogenic fuel tank (10). According to claim 6,
The fourth section (32.4) of the instrument guide pipe (32) comprises a float portion (40) arranged to reflect radar signals. According to claim 1,
A cryogenic fuel tank (10), wherein the metrology arrangement (30) comprises an inertial measurement unit for defining an inclination angle of the cryogenic fuel tank (10). According to claim 1,
The cryogenic fuel tank (10) is provided with two separate metrology arrangements (30) comprising a temperature measurement system (34') and a radar-based liquid measurement system (34). Fuel tank (10). According to claim 3,
The metrology arrangement (30) comprises a radar-based measurement system (34), wherein a fourth section (32.4) of the instrument guide pipe (32) comprises a static reference reflector (42) in the pipe (32). Cryogenic fuel tank (10). delete

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