EP3112740A1

EP3112740A1 - Cryogenic tank

Info

Publication number: EP3112740A1
Application number: EP15001976.8A
Authority: EP
Inventors: Philip Werner
Original assignee: Linde GmbH
Current assignee: Linde GmbH
Priority date: 2015-07-02
Filing date: 2015-07-02
Publication date: 2017-01-04

Abstract

The invention relates to a cryogenic tank (100) with an inner vessel (110), an outer vessel (120) and suspension means (210, 220, 230) for suspension of the inner vessel (110) in the outer vessel (120), wherein first suspension means (210) comprise blocks (211) arranged on an inner surface (125) of the outer vessel (120), an outer surface (115) of the inner vessel (110) resting on a surface of the blocks (211) and the blocks (211) moving freely against the outer surface (115) of the inner vessel (110), and/or wherein second suspension means (220) comprise longitudinal bars (221, 222), wherein one end (221 a, 222b) of each longitudinal bar (221, 222) is fixated on the inner surface (125) of the outer vessel (120) and the other end (221 b, 222a) of each longitudinal bar (221, 222) is fixated on the outer surface (115) of the inner vessel (110), the longitudinal bars (221, 222) in a projection onto the inner surface (125) of the outer vessel (120) or onto the outer surface (115) of the inner vessel (110) extending in a longitudinal direction, and/or wherein third suspension means (230) comprise circumferential bars, wherein one end of each circumferential bar is fixated on the inner surface (125) of the outer vessel (120) and the other end of each circumferential bar is fixated on the outer surface (115) of the inner vessel (110), the circumferential bars in a projection onto the inner surface (125) of the outer vessel (120) or onto the outer surface (115) of the inner vessel (110) extending in a circumferential direction.

Description

The present invention relates to a cryogenic tank with an inner vessel, an outer vessel and suspension means for suspension of the inner vessel in the outer vessel.

Prior art

Cryogenic tanks, especially in the form of so-called bullet tanks, can be used for storage of liquefied cryogenic gases with typical temperatures below -150°C, for example liquid air gases or liquid natural gas. Cryogenic tanks can comprise an inner vessel and an outer vessel, wherein the inner vessel is suspended in the outer vessel. The space between the inner vessel and the outer vessel can be evacuated. This vacuum between the inner and the outer vessel serves as a heat insulation of the cryogenic tank.
Suspension means for suspension of the inner vessel in the outer vessel are usually designed for cryogenic tanks with capacities up to 500 m³. For larger cryogenic tanks, especially with capacities larger than 1000 m³, these kinds of suspension means are not suitable.
Thus, it is desirable to provide an improved cryogenic tank, especially with a capacity larger than 1000 m³, with improved suspension means for suspension of an inner vessel in an outer vessel.

Disclosure of the invention

According to the invention, a cryogenic tank, especially in the form of a bullet tank, with the features of the independent claim 1 is suggested. Preferred embodiments and advantages of the invention are subject of the dependent claims and of the following description.
The cryogenic tank comprises an inner vessel, an outer vessel and suspension means for suspension of the inner vessel in the outer vessel.
First suspension means comprise blocks arranged on an inner surface of the outer vessel, an outer surface of the inner vessel resting on a surface of the blocks and the blocks moving freely against the outer surface of the inner vessel.
Alternatively or additionally, second suspension means comprise longitudinal bars. One end of each longitudinal bar is fixated on the inner surface of the outer vessel and the other end of each longitudinal bar is fixated on the outer surface of the inner vessel. The longitudinal bars in a projection onto the inner surface of the outer vessel or onto the outer surface of the inner vessel extend in a longitudinal direction of the cryogenic tank. A longitudinal direction is especially a direction parallel to a main axis of the inner vessel.
In said projection, each longitudinal bar especially extends essentially only in the longitudinal direction, i.e. in a direction parallel to the main axis of the inner vessel. A component of the extension of each longitudinal bar in the longitudinal direction is especially larger than a component of the extension in a direction perpendicular to the main axis of the inner vessel.
Alternatively or additionally, third suspension means comprise circumferential bars. One end of each circumferential bar is fixated on the inner surface of the outer vessel and the other end of each circumferential bar is fixated on the outer surface of the inner vessel. The circumferential bars in a projection onto the inner surface of the outer vessel or onto the outer surface of the inner vessel extend in a circumferential direction of the cryogenic tank.
In said projection, each circumferential bar especially extends essentially only in the circumferential direction, i.e. in a direction tangentially to the cross-section of the inner vessel. A component of the extension of each circumferential bar in this tangential direction is especially larger than a component of the extension in a direction perpendicular to said tangential direction.

Advantages of the invention

By the suspension means according to the present invention a suspension of the inner vessel in the outer vessel is provided, able to take loads and compensate forces in all directions and to provide a safe support of the inner vessel. The suspension means also provides a safe support during transport of the cryogenic tank, during which loads and forces in different directions can occur and can change rapidly. The cryogenic tank can also be mounted on a ship and loads and forces due to rough sea can be compensated. The suspension is also suitable for cryogenic tanks located at sites, where seismic activities can occur. The cryogenic tank can safely be mounted at such kinds of sites and the suspension means secure the cryogenic tank against loads and forces due to seismic activities.
The suspension means are especially not sensitive to tolerances. The inner and the outer vessel can be assembled with much larger tolerances than with state of the art suspensions, especially with tolerances in the range of ±50 mm. It can be very difficult and time consuming to move, to lift and to precisely position the inner and the outer vessel with high accuracy. This is especially the case for comparatively heavy and large inner and outer vessels with comparatively thin shells (i.e. the plates or sheets forming the cylindrical shell of the inner and outer vessel are very thin compared to the diameter of the respective vessels). The suspension means provide save support for the cryogenic vessel according to the invention, without having to position the inner and outer vessel with very high accuracy. The inner vessel can especially be positioned in the outer vessel in a short amount of time. After the inner vessel is positioned in the outer vessel, the second and third suspension means can easily be fixated to the inner and outer vessel, especially by welding.
Shrinkage of the inner vessel and outer vessel can be compensated by the suspension means. The temperature of an empty cryogenic tank usually corresponds roughly to the outside temperature. If the inner vessel is being filled with liquefied gas, the inner vessel cools down very quickly. In the case of liquid nitrogen, the inner vessel can cool down to temperatures of about -200°C. Due to that temperature change, the inner vessel shrinks. The outer vessel, however, does not cool down at filling. Thus, the outer vessel does not shrink when the inner vessel is filled with cold gas. By the suspension means these differences can be compensated without any stresses or damages to the vessels and to the suspension means. The shrunk inner vessel can still safely be supported and suspended in the less shrunk outer vessel. The inner vessel particularly still rests on the blocks of the first suspension means when the inner and the outer vessel are unequally shrunk.
The first suspension means especially support the inner vessel and take loads and forces in directions perpendicular to the main axis of the inner vessel (lateral support, vertical support). The outer surface of the inner vessel is especially not fixated to the blocks. There are especially no means on the outer surface of the inner vessel in order to fix the blocks to particular positions of the outer surface of the inner vessel. The inner vessel can particularly glide along the blocks in direction parallel to its main axis. The outer surface of the inner vessel is especially constructed smooth in order to enable this gliding of the inner vessel along the blocks.
Preferably, the blocks are made of epoxy, especially of fibre reinforced plastic (FRP) or glass fibre reinforced epoxy (fibreglass). The blocks are comparatively small in relation to the cryogenic tank, as well as in relation to the second and third suspension means. The length of the epoxy bricks can especially be in the range between 500 m and 1000 mm, the width can especially be in the range between 10 mm and 50 mm, the height can especially be in the range between 100 mm and 200 mm.
The second suspension means especially support the inner vessel and take loads and forces in a direction parallel to the main axis of the inner vessel (longitudinal support). The longitudinal bars are especially constructed as comparatively long, slender stripes. Advantageously, the longitudinal bars and/or the circumferential bars are made of stainless steel, especially of stainless steel type 304 according to European standard 1.4301 (also referred to as 18/8 stainless steel).
The third suspension means especially prevent a relative motion of the inner and the outer vessel (rotational constraint). Thus, the inner and the outer vessel are especially secured against twisting. Rotation of the inner and the outer vessel relative to each other around the main axis of the inner vessel can be prevented. By rotations of this kind, elements arranged between the inner and the outer vessel (for example pipes or valves) can be damaged. The third suspension means prevent such damage of such elements. Also damage to the second suspension means due to rotation of the vessels can be prevented.
The cryogenic tank is particularly constructed as a horizontal tank. The cryogenic tank especially comprises saddles fixed to the ground, on which it rests. Those saddles can for example be made of steel type S355 according to standard EN 10025-2 or of stainless steel type 304
The cryogenic tank is especially constructed to store liquefied gases, expediently liquid air gases or liquid natural gas. In the space between the inner vessel and the outer vessel fluid-elements for filling and emptying the inner vessel can be arranged, for example pipes and/or valves. For instance pipes can be used, which are constructed according to the standards NPS (Nominal Pipe Size) or DN (Diametre Nominal).
The cryogenic tank is especially constructed to create a vacuum in the space between the inner and the outer vessel. Thus, the cryogenic tank can be vacuum insulated. The inner vessel and the outer vessel, respectively, especially form a vacuum jacket, especially according to EN 13458-2. The outer surface of the inner vessel and/or the inner surface of the outer vessel can be enforced with stiffening rings, according to to EN 13458-2 (paragraph 4.3.6.2.6).
The inner vessel is especially made of stainless steel or austenitic stainless steel, expediently of stainless steel type 304. The outer vessel can especially be made of carbon steel or stainless steel, expediently of steel P265GH according to standard EN 10028 or also of stainless steel type 304. The inner and the outer vessel are especially constructed according to the standard EN 13458-2 titled "Cryogenic vessels - Static vacuum insulated vessels - Part 2: Design, fabrication, inspection and testing".
According to EN 13458-2 (paragraph 4.3.3.4), the safety factor S_k of the outer surface with respect to external pressure is essentially S_k = 2. The safety factor S_k is especially defined as the material strength of the material the outer vessel is made of divided by the maximum load which it can withstand.
Advantageously, the blocks are arranged circumferentially on the inner surface of the outer vessel at least at two different locations of the cryogenic tank in reference to a direction parallel to the main axis of the inner vessel. That means at each of these at least two locations a number of blocks are arranged along a ring segment or ring on the outer vessel's inner surface. The inner and/or the outer vessel can especially be enforced with stiffening rings at these locations.
Alternatively or additionally, the longitudinal bars are preferably circumferentially arranged at one location of the cryogenic tank in reference to a direction parallel to the main axis of the inner vessel. Analogously to the blocks, at this location a number of longitudinal bars are arranged along a ring segment or along a ring on the outer vessel's inner surface and the inner vessel's outer surface, respectively.
The specific design of the suspension with the blocks arranged at least at two different locations and with the longitudinal bars arranged at one specific location is particularly convenient in order to compensate shrinkage of the inner and outer vessel due to temperature differences. Since the longitudinal bars are fixated on the inner vessel as well as on the outer vessel, shrinkage or expansion of the vessels could negatively affect the longitudinal bars or could possibly even lead to stresses and damages. However, this danger can especially be avoided by arranging the longitudinal bars only at one specific location, since these longitudinal bars can particularly adapt to the different sizes of the inner and outer vessel. There is especially no danger of longitudinal bars arranged at different locations being damaged due to shrinkage and expansion of the vessels. The shrinking inner vessel can especially glide along the blocks in direction parallel to its main axis. The blocks at the different locations can support the inner vessel in directions perpendicular to the main axis also when the inner and outer vessel shrink. Tilting of the shrunk inner vessel relative to the shrunk outside vessel can be prohibited.
The longitudinal bars are particularly arranged at one of the locations, at which also blocks of the first suspension means are arranged. The blocks at this location are arranged on a ring segment, which runs through points, e.g. the middles of the distances, between the fixation points of the longitudinal bars, at which the longitudinal bars are fixated to the outer vessel and the inner vessel, respectively. Thus, the (longitudinal) support in direction parallel to the main axis of the inner vessel is especially applied relative to fixed points on this ring segment.
The cryogenic tank particularly comprises two saddles, wherein each of them is arranged at one of the locations, at which blocks of the first suspension means are arranged. One saddle is especially arranged at that location, at which blocks as well as the longitudinal bars are arranged. That saddle is especially fixed to the ground in a direction parallel and perpendicular to the main axis. The other one of the two saddles is especially fixed to ground only in direction perpendicular to the main axis. Thus, this other one of the two saddles can especially glide along the ground in direction parallel to the main axis.
Preferentially, the third suspension means comprise two circumferential bars arranged at the centre bottom of the cryogenic tank. These two circumferential bars are especially arranged in pairs and are arranged next to each other, expediently arranged comparatively close to each other. The circumferential bars are especially arranged in an X-form seen from a front side of the vessel, i.e. one of these two circumferential bars is fixated with its first end on the inner surface of the outer vessel and with its second end on the outer surface of the inner vessel, while the other circumferential bar is fixated with its corresponding first end on the outer surface of the inner vessel and with its corresponding second end on the inner surface of the outer vessel. With the third suspension means comprising only two circumferential bars arranged comparatively close to each other there is especially no danger of circumferential bars located at different locations being damaged due to shrinkage and expansion of the inner and outer vessels.
Preferably, the blocks of the first suspension means are arranged on the inner surface of the outer vessel in a way that the blocks are not moveable in a direction parallel to the main axis of the inner vessel. Thus, the inner vessel can glide on the blocks in direction parallel to the main axis without the blocks themselves moving in that direction.
Advantageously, the blocks of the first suspension means are arranged in slots formed in or on the inner surface of the outer vessel. In a front end and/or in a rear end of these slots (regarding to a direction parallel to the main axis) fixation means like plates or chocks can be arranged in order to prevent the blocks from moving in a direction parallel to the main axis.
Preferably, the blocks are arranged in respect of the main axis of the inner vessel circumferentially in equidistant angular distances on the inner surface of the outer vessel. This equidistant angular distance is preferably between 10° and 20°. Advantageously, the blocks are arranged in equidistant angular distances of essentially 15°.
Preferentially, the blocks are circumferentially distributed over an angular range between 160° and 180° on the inner surface of the outer vessel. Advantageously, the blocks are circumferentially distributed over a range of essentially 170°. The blocks are especially distributed over both lower quadrants of the outer vessel's cross-section. Preferably, the blocks are distributed over both circular sectors starting from the lowermost point, i.e. from the centre bottom of the outer vessel's inner surface with an angle of essentially 85° in respect to the main axis of the inner vessel.
Advantageously, the length of the longitudinal bars of the second suspension means and/or the length of the circumferential bars of the third suspension means is considerably larger than their respective width, especially between five times and twenty-five times as large as their respective width, especially essentially twenty times as large as their respective width. Preferably, also the width of the longitudinal bars and/or the width of the circumferential bars is considerably larger than their respective height, especially between five times and twenty-five times as large as their respective height, especially essentially twenty times as large as their respective height.
The longitudinal bars have its largest extension especially in the longitudinal direction, i.e. in a direction parallel to the main axis of the inner vessel. The length of the longitudinal bars is especially in the range between 2 m and 10 m, preferentially essentially 5 m. Their width is especially in the range between 100 mm and 300 mm, their height in the range between 10 mm and 15 mm. Due to that construction, the longitudinal bars can provide safe support of the inner vessel in direction parallel to its main axis, also for a cryogenic tank with a capacity larger than 1000 m³.
The length of the circumferential bars is especially in the range between 3.0 m and 3.5 m. Their width is especially in the range between 100 mm and 300 mm, their height in the range between 10 mm and 15 mm.
Advantageously, the longitudinal bars are arranged in pairs. The two longitudinal bars of each pair are arranged next to each other. They are especially arranged comparatively close to each other. The longitudinal bars of each pair are especially arranged in an X-form seen from a side of the vessel, i.e. one of the two longitudinal bars of each pair is fixated with its first end on the inner surface of the outer vessel and with its second end on the outer surface of the inner vessel, while the other longitudinal bar of each pair is fixated with its corresponding first end on the outer surface of the inner vessel and with its corresponding second end on the inner surface of the outer vessel.
Preferably, the longitudinal bars and/or the circumferential bars are pre-stressed. Thus, an even load distribution can especially be provided and it can be guaranteed that all longitudinal bars can bear equal loads. The longitudinal and/or circumferential bars are especially pre-stressed when they are mounted in the cryogenic tank.
Advantageously, the volume of the inner vessel is between 300 m³ and 2000 m³, especially between 1000 m³ and 1800 m³. The suspension means provide a reliable and safe suspension of the inner vessel in the outer vessel for cryogenic tanks larger than 300 m³ and especially larger than 1000 m³. The length of the outer vessel is preferably between 20 m and 50 m, advantageously especially between 30 m and 45 m. The diameter of the outer vessel is preferably between 4 m and 9 m, advantageously between 6.5 m and 8 m.
The thickness in material of the inner vessel and of the outer vessel is between 12 mm and 20 mm each. The thickness of the inner and outer vessels' lateral surfaces is especially in the range between 12 mm and 15 mm each, the thickness of the vessels' ends is especially in the range between 15 mm and 19 mm each. The inner and the outer vessel are each especially made of sheets or plates. The length of these sheets (i.e. the extension in direction parallel to the main axis of the inner vessel) is especially between 2 m and 2.5 m, particularly essentially 2.3 m. The inner vessel and the outer vessel are especially each made of about 13 to 15 sheets each.
The distance in direction parallel to the main axis of the inner vessel between the inner vessel and the outer vessel is preferably between 0.5 m and 2.0 m, preferably between 0.8 m and 1.2 m, advantageously essentially 1.0 m. The distance in direction perpendicular to the main axis of the inner vessel between the inner vessel and the outer vessel is preferably between 0.1 m and 1.0 m, preferably between 0.2 m and 0.6 m, advantageously essentially 0.4 m. Thus, enough space between the inner and the outer vessel is provided in order to arrange all the necessary fluid-elements.
Further advantages and embodiments of the invention will become apparent from the description and the appended Figures.
It should be noted that the previously mentioned features and the features to be further described in the following are usable not only in the respectively indicated combination, but also in further combinations or taken alone, without departing from the scope of the present invention.
In the drawings:

FIG. 1: schematically shows a cryogenic tank according to a preferred embodiment of the invention in a sectional side view,
FIG. 2: schematically shows a part of a cryogenic tank according to a preferred embodiment of the invention in a sectional front view,
FIG. 3: schematically shows a part of a cryogenic tank according to a preferred embodiment of the invention in a perspective view,
FIG. 4: schematically shows a part of a cryogenic tank according to a preferred embodiment of the invention in a perspective view,
FIG. 5: schematically shows a part of a cryogenic tank according to a preferred embodiment of the invention in a perspective view,
FIG. 6: schematically shows a part of a cryogenic tank according to a preferred embodiment of the invention in a perspective view, and
FIG. 7: schematically shows a cryogenic tank according to a preferred embodiment of the invention in a sectional front view.

Detailed description of the drawings

In FIG. 1 a cryogenic tank 100 according to a preferred embodiment of the invention is shown in a sectional side view. The cryogenic tank 100 comprises an inner vessel 110 and an outer vessel 120. The inner vessel 110 is suspended in the outer vessel 120 by first suspension means 210, second suspension means 220, and third suspension means 230.
The inner vessel 110 extends in a longitudinal direction along a main axis 111. This main axis 111 especially corresponds to a longitudinal axis of the inner vessel 110. In this example, the length l₁₁₀ of the inner vessel 110 in direction along this main axis 111 is 33.0 m. The length l₁₂₀ of the outer vessel 120 in direction along this main axis 111 is 34.8 m. The diameter d₁₁₀ of the inner vessel 110 is for instance 7.2 m. The diameter d₁₂₀ of the outer vessel 120 is for instance 8.0 m. A distance d_X between the inner vessel 110 and the outer vessel 120 in direction along the main axis 111 of the inner vessel 110 is for instance 0.9 m.
The first suspension means comprise blocks 211 arranged on an inner surface 125 of the outer vessel 120, an outer surface 115 of the inner vessel 110 resting on a surface of the blocks 211 and the blocks moving freely against the outer surface 115 of the inner vessel 110. A first number of blocks 211 are arranged at a first location 101 of the cryogenic tank 100 and a second number of blocks 211 are arranged at a second location 102 of the cryogenic tank 100.
The second suspension means 220 comprise longitudinal bars 221, 222. The longitudinal bars 221, 222 are arranged at the second location 102 of the cryogenic tank 100. The longitudinal bars 221, 222 are arranged in pairs 225. The longitudinal bars 221, 222 of each pair 225 are arranged in an X-form seen from the side view of FIG. 1. A first end 221 a of a first longitudinal bar 221 of each pair 225 is fixated on an inner surface 125 of the outer vessel 120, whereas a corresponding first end 222a of a second longitudinal bar 222 of each pair 225 is fixated on the outer surface 115 of the inner vessel 110. Analogously, a second end 221 b of the first longitudinal bar 221 of each pair 225 is fixated on the outer surface 115 of the inner vessel 110, whereas a corresponding second end 222b of the second longitudinal bar 222 of each pair 225 is fixated on the inner surface 125 of the outer vessel 120.
The dimension of each block 211 in this example is 600 mm × 150 mm × 40 mm. The dimensions of each longitudinal bar 221, 222 in this example is 5000 mm × 250 mm × 12 mm. Thus, the length of 5 m of the longitudinal bars 221, 222 is twenty times as large as their width of 250 mm. The blocks 211 are especially made of epoxy, especially of glass fibre reinforced epoxy (fibreglass). The longitudinal bars 221, 222 are made of stainless steel, especially of stainless steel type 304.
The cryogenic tank is especially constructed as a horizontal tank. The main axis 111 is especially parallel to the ground on which the cryogenic tank 100 is mounted. An axis 112 (vertical axis) is perpendicular to the main axis 111 and especially perpendicular to the ground on which the cryogenic tank 100 is mounted. An axis 113 is also especially parallel to the ground and perpendicular to the axes 111 and 112. The axis 113 is perpendicular to the drawing plane of FIG. 1. The axes 111, 112, 113 especially form an orthogonal coordinate system.
Each longitudinal bar 221, 222 extends in a direction parallel to the main axis 111 as well as in directions perpendicular to the main axis 111, i.e. in directions parallel to the axes 112 and 113. Since the length of the longitudinal bars 221, 222 is considerably larger than their width, a component of the extension of each longitudinal bar 221, 222 in a direction parallel to the main axis 111 is larger than components of their extension in directions perpendicular to the main axis 111. A projection of the longitudinal bars 221, 222 onto the inner surface 125 of the outer vessel 120 or onto the outer surface 115 of the inner vessel 110 extends in the longitudinal direction, i.e. parallel to the main axis 111.
The third suspension means 230 comprise two circumferential bars, arranged at a third location 103 of the cryogenic tank 100. The third suspension means 230 are hereafter described in reference to FIG. 2. In FIG. 2, a part of the cryogenic tank 100 of FIG. 1 is schematically shown in a sectional front view.
FIG. 2 shows a lower part of the cryogenic tank 100 at the third location 103. The circumferential bars 231 and 232 are arranged at the centre bottom of the cryogenic tank 100. A first end 231a of a first circumferential bar 231 is fixated on the inner surface 125 of the outer vessel 120, whereas a first end 232a of a second circumferential bar 232 is fixated on the outer surface 115 of the inner vessel 110. A second end 231 b of the first circumferential bar 231 is fixated on the outer surface 115 of the inner vessel 110, whereas a second end 232b of the second circumferential bar 232 is fixated on the inner surface 125 of the outer vessel 120.
The circumferential bars 231, 232 especially extend roughly only in directions tangentially to the cross-section of the inner vessel 110. Thus, a component of the extension of each circumferential bar 231, 232 in this tangential direction is larger than a component of the extension in directions perpendicular to this tangential direction. A projection of the circumferential bars 231, 232 onto the inner surface 125 of the outer vessel 120 or onto the outer surface 115 of the inner vessel 110 extends in a circumferential direction, i.e. perpendicular to the main axis 111.
The dimensions of the circumferential bars 231, 232 in this example are especially 1000 mm × 200 mm × 12 mm. The circumferential bars 231, 232 are made of stainless steel, especially of stainless steel type 304.
In each of the Figures 3 and 4 a part of the cryogenic tank 100 of FIG. 1 is schematically shown in a perspective view. FIG. 3 shows the inner surface 125 of the outer vessel 120 at the first location 101. FIG. 4 shows the outer surface 115 of the inner vessel 110 at the first location 101.
As can be seen in FIG. 3, the blocks 211 of the first suspension means 210 are arranged on the inner surface 125 of the outer vessel 120. The blocks are especially arranged in slots formed on the inner surface 125. The blocks 211 are fixed in these slots in order to prevent them from moving in direction parallel to the main axis 111. For this purpose, fixation means like plates are arranged in a front end and in a rear end of each slot.
As can be seen in FIG. 4, the outer surface 115 of the inner vessel 110 rests on the surface of the blocks 211. The inner vessel 110 can be enforced with a stiffening ring 116 at this location 101, at which it rests on the blocks. Since the blocks 211 are not fixed to the outer surface 115, the inner vessel 110 can glide along the blocks 211 in direction parallel to the main axis 211 if necessary.
In each of the Figures 5 and 6 another part of the cryogenic tank 100 of FIG. 1 is schematically shown in a perspective view analogously to Figures 3 and 4. FIG. 5 shows the inner surface 125 of the outer vessel 120 at the second location 102. FIG. 6 shows the outer surface 115 of the inner vessel 110 at the second location 102.
As can be seen in Figures 5 and 6, the longitudinal bars 221, 222 are arranged in pairs 225 with the first end 221 a of the first longitudinal bar 221 and the second end 222b of the second longitudinal bar 222 being fixated on the inner surface 125 of the outer vessel 120 and with the first end 221 b of the first longitudinal bar 221 and the second end 222a of the second longitudinal bar 222 being fixated on the outer surface 115 of the inner vessel 110.
Hereafter, the special arrangement of the blocks 211 and the longitudinal bars 221, 222 will be explained in reference to FIG. 7, which schematically shows the cryogenic tank 100 in a sectional front view at the second location 102.
At the second location 102, twelve blocks 211 are circumferentially arranged. These twelve blocks are arranged in a lower half, i.e. in both lower quadrants of the outer vessel's inner surface 125. The blocks 211 are arranged in equidistant angular distances on the inner surface 125 of α = 15° in respect of the main axis 111.
The blocks 211 are circumferentially distributed over an angular range of β = 170° on the inner surface 125 of the outer vessel 120. Thus, the blocks 211 are distributed over both circular sectors starting from the lowermost point, i.e. from the centre bottom of the inner surface 125 of the outer vessel 120 with an angle of 0.5×β = 85°.
There are also twelve blocks 211 arranged at the first location analogously to the twelve blocks 211 at the second location with equidistant angular distances of α = 15°, circumferentially distributed over a range of β = 170°.
Moreover, at the second location 102 a number of six pairs 225 of longitudinal bars 221, 222 are circumferentially arranged on the inner surface 125 of the outer vessel 120 and on the outer surface 115 of the inner vessel 110, respectively. The pairs 225 of longitudinal bars 221, 222 are arranged in equidistant angular distances of γ = 60°.

Reference list

100: cryogenic tank
101: first location
102: second location
103: third location

110: inner vessel
111: main axis
112: axis
113: axis
115: outer surface of inner vessel
116: stiffening ring
120: outer vessel
125: inner surface of outer vessel

210: first suspension means
211: blocks

220: second suspension means
221: longitudinal bar
221a: first end of longitudinal bar
221b: second end of longitudinal bar
222: longitudinal bar
222a: first end of longitudinal bar
222b: second end of longitudinal bar
225: pair of longitudinal bars

230: third suspension means
231: circumferential bar
231a: first end of circumferential bar
231b: second end of circumferential bar
232: circumferential bar
232a: first end of circumferential bar
232b: second end of circumferential bar
l₁₁₀: length of the inner vessel
l₁₂₀: length of the outer vessel
d₁₁₀: diameter of the inner vessel
d₁₂₀: diameter of the outer vessel
d_X: distance between first and second vessel

α: angular distance between blocks
β: range over which the blocks are distributed
γ: angular distance between longitudinal bars

Claims

Cryogenic tank (100) with an inner vessel (110), an outer vessel (120) and suspension means (210, 220, 230) for suspension of the inner vessel (110) in the outer vessel (120),
characterised in, that
- first suspension means (210) comprise blocks (211) arranged on an inner surface (125) of the outer vessel (120), an outer surface (115) of the inner vessel (110) resting on a surface of the blocks (211) and the blocks (211) moving freely against the outer surface (115) of the inner vessel (110), and/or that

- second suspension means (220) comprise longitudinal bars (221, 222), wherein one end (221 a, 222b) of each longitudinal bar (221, 222) is fixated on the inner surface (125) of the outer vessel (120) and the other end (221 b, 222a) of each longitudinal bar (221, 222) is fixated on the outer surface (115) of the inner vessel (110), the longitudinal bars (221, 222) in a projection onto the inner surface (125) of the outer vessel (120) or onto the outer surface (115) of the inner vessel (110) extending in a longitudinal direction of the cryogenic tank (100) and/or that

- third suspension means (230) comprise circumferential bars (231, 232), wherein one end (231 a, 232b) of each circumferential bar (231, 232) is fixated on the inner surface (125) of the outer vessel (120) and the other end (231 b, 232a) of each circumferential bar (231, 232) is fixated on the outer surface (115) of the inner vessel (110), the circumferential bars (231, 232) in a projection onto the inner surface (125) of the outer vessel (120) or onto the outer surface (115) of the inner vessel (110) extending in a circumferential direction of the cryogenic tank (100).
Cryogenic tank (100) according to claim 1, wherein the blocks (211) of the first suspension means (210) are arranged circumferentially on the inner surface (125) of the outer vessel (120) at least at two different locations (101, 102) of the cryogenic tank (100) in reference to a direction parallel to the main axis (111) of the inner vessel (110).
Cryogenic tank (100) according to claim 1 or 2, wherein the longitudinal bars (221, 222) of the second suspension means (220) are circumferentially arranged at one location (102) of the cryogenic tank (100) in reference to a direction parallel to the main axis (111) of the inner vessel (110).
Cryogenic tank (100) according to any one of the previous claims, wherein the third suspension means (230) comprise two circumferential bars (231, 232) arranged at the centre bottom of the cryogenic tank (100).
Cryogenic tank (100) according to any one of the previous claims, wherein the blocks (211) of the first suspension means (210) are arranged on the inner surface (125) of the outer vessel (120) in a way, that the blocks are not moveable in a direction parallel to the main axis (111) of the inner vessel.
Cryogenic tank (100) according to any one of the previous claims, wherein the blocks (211) of the first suspension means (210) are arranged in slots formed in or on the inner surface (125) of the outer vessel (120).
Cryogenic tank (100) according to any one of the previous claims, wherein the blocks (211) of the first suspension means (210) are arranged in respect of the main axis (111) of the inner vessel (110) circumferentially in equidistant angular distances (α) on the inner surface (125) of the outer vessel (120), especially in angular distances (α) between 10° and 20°, especially in angular distances (α) of essentially 15°.
Cryogenic tank (100) according to any one of the previous claims, wherein the blocks (211) of the first suspension means (210) are circumferentially distributed in respect of the main axis (111) of the inner vessel (110) over an angular range (β) between 160° and 180° on the inner surface (125) of the outer vessel (120), especially in a range (β) of essentially 170°.
Cryogenic tank (100) according to any one of the previous claims, wherein the length of the longitudinal bars (221, 222) of the second suspension means (220) is considerably larger than their width, especially between five times and 25 times as large as their width, especially essentially 20 times as large as their width.
Cryogenic tank (100) according to any one of the previous claims, wherein the longitudinal bars (221, 222) and/or the circumferential bars (231, 232) are arranged in pairs (225).
Cryogenic tank (100) according to claim 10, wherein two bars arranged next to each other form a pair of longitudinal bars (221, 222) or a pair of circumferential bars (231, 232), one of these two bars being fixated with its first end on the inner surface (125) of the outer vessel (120) and with its second end on the outer surface (115) of the inner vessel (110), while the other one of these two bars being fixated with its corresponding first end on the outer surface (115) of the inner vessel (110) and with its corresponding second end on the inner surface (125) of the outer vessel (120).
Cryogenic tank (100) according to any one of the previous claims, wherein the longitudinal bars (221, 222) and/or the circumferential bars (231, 232) are pre-stressed.
Cryogenic tank (100) according to any one of the previous claims, wherein the volume of the inner vessel (110) is between 300 m³ and 2000 m³, especially between 1000 m³ and 1800 m³.
Cryogenic tank (100) according to any one of the previous claims, wherein the length (l₁₂₀) of the outer vessel (120) is between 20 m and 50 m, especially between 30 m and 45 m, and wherein the diameter (d₁₂₀) of the outer vessel (120) is between 4 m and 9 m, especially between 6.5 m and 8 m.
Cryogenic tank (100) according to any one of the previous claims, wherein the distance (d_X) in direction parallel to the main axis (111) of the inner vessel (110) between the inner vessel (110) and the outer vessel (120) is between 0.5 m and 2.0 m, especially between 0.8 m and 1.2 m, and wherein the distance in direction perpendicular to the main axis (111) of the inner vessel (110) between the inner vessel (110) and the outer vessel (120) is between 0.1 m and 1.0 m, especially between 0.2 m and 0.6 m.