DE1158536B - Storage tank for the storage of liquefied gases - Google Patents

Description

INTERNAT. KL. F 25 j

GERMAN

PATENT OFFICE

C19237Ia / 17g

REGISTRATION DATE: JUNE 18, 1959

NOTICE
THE REGISTRATION
AND ISSUE OF THE
EDITORIAL: DECEMBER 5, 1963

The invention relates to a storage tank for storing liquefied gases at normal pressure and low temperatures, consisting of one arranged inside a jacket made of heat-insulating material, at least partially adjacent to this jacket lining made of a thin flexible Foil of a liquid-tight, non-self-supporting material.

In known storage tanks of this type, the inner skin is attached to the insulation so that it is at completely or partially empty tank does not fall inwards due to its flexibility. Because the inner skin due to the large temperature differences to which it is exposed when the tank is in operation Changes in their dimensions due to thermal expansion and contraction must the inner skin in the known tanks is either sufficiently stretchable or corrugated to prevent the skin from tearing. Regardless of which of these two options is chosen, results in the known tanks already from the fact that the inner skin at all on the underlying, much less expanding and contracting insulation attached must be, a disadvantage in that the attachment of the inner skin is time consuming and expensive.

The object on which the invention is based is to develop a storage tank of the type mentioned at the beginning To propose kind that avoids the disadvantages of the known device and a proposal does this without attaching the inner skin to the one adjoining it on the outside Insulation get along even when building larger tanks.

To solve this problem, the invention provides that the upwardly open lining is supported by means of horizontally arranged annular parts, which are connected to the inside of the liner at its upper end and at one or more points between the upper end and the bottom plate the liner, the annular parts being suspended in the upper part of the container or are supported in the lower part of the container.

Here, the ring-shaped parts can consist of horizontally arranged spiders through Cables are interconnected and attached to the top of the tank by cables.

It is advantageous to use spiders consisting of an outer ring and an inner ring, with the rings are connected to each other by radial arms.

Storage tank for storage
liquefied gases

Applicant:

Conch International Methane Limited,
Nassau, Bahamas (British West Indies)

Representative: Dipl.-Ing. K.-A. Brose, patent attorney.
Pullach near Munich, Wiener Str. 2

Claimed priority:

V. St. v. America 9 July 1958

(No. 747 418 and No. 747 413)

Cornelius DeRode Dosker, Louisville, Ky. (V. St. Α.), Has been named as the inventor

This not only gives the rings greater strength, but it is also possible now to attach the inner ring of the top spider to the top of the tank by cables and to connect the outer rings of the remaining spiders together. This will make the suspension of the whole Arrangement inside the tank facilitated. The invention is described below with reference to in the drawing illustrated embodiments explained in more detail. It shows

Fig. 1 is a vertical section through a tank according to the invention,

Fig. 2 is a section on the line 2-2 in Fig. 1,
3 shows a section through the side wall of the tank on the line 3-3 according to FIG. 1,
Fig. 4 is a section on the line 4-4 of Fig. 1 in an enlarged view,

FIG. 5 shows an enlarged partial section through the lower part of the tank according to FIG. 1,

6 shows a corresponding section through the upper end piece of the lining,

7 is a plan view of a spider,
8 shows a vertical section through another embodiment,

9 shows a horizontal section through the side wall of a tank according to FIG. 8,

FIG. 10 shows a vertical section through the bottom of a tank according to FIG. 8,

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3 4

Fig. 11 is a partial section through the lining surface 40 of the planks 36 with an approximately

and V-shaped recess, which the under

FIG. 12 shows a section corresponding to FIG. 11 at an angle meeting plates 28

by another embodiment. their liaison. Each of the panels

The tank denoted by 10 in Fig. 1 consists of 5 28 is near its edge by means of a bolt

a base ring 12, which is preferably made of 42, which passes through the plank and the outer hardwood

tetem wood is formed, therefore for the required panel 32 of the panel 28 in question, at

Provides strength, has a long service life and one of the planks 36 is attached. From the inner one

is still relatively easy. The plates 28 each have an identical ring surface

is arranged at the top of the tank 10. Two 10 conically shaped plugs 44 cut out to

additional rings 14 are both above the base ring and the inner head of the bolt in question

12 and arranged under the top ring 12, from 42 when assembling or replacing the

to which the curved, vertically running ribs make insulating panels accessible. The plugs 44

16, which form the frame of the tank 10. after the corresponding bolt 42 is tightened

As can be seen from the drawing, the 15 has been drawn, reinserted, in order to

Rings 14 have a larger inner diameter than the borrowed uniform insulation of the storage space

Rings 12, but to produce a smaller outer diameter.

than the corresponding rings 12, so that the lower Although the construction of the insulating panels made of wood

Ring 14 can rest on the lower base ring 12, contraction and expansion of the panels

and the ring 12 with a part 18 outwardly reduces to a minimum over 20, one nevertheless occurs

the lower ring and with a part 20 inward relative movement of a lesser extent between the

protrudes over the lower ring 14. Plates 28 when the temperature in the storage

The rings 14 are also preferably changed from storage space by a large amount. It is layered wood produced and, as Fig. 2 shows, with therefore recommended, the connection points of the Dovetail-like, vertical grooves 22 on 25 plates 28 according to the manner shown in FIG. 3 from outer circumference nec provided. Each of the grooves 22 seals. For this purpose, the inner edges of the the correspondingly formed end 24 of one of the plates 28 bevelled so that V-shaped hollow ribs 16 on. The ribs 16 are formed in the circumferential direction between the plates, in which seal are inserted on the device strip 48 separated from one another by gaps. The Stripes 48 Arranged on the outer periphery of the tank 10. The ribs 30 are next to the corresponding bevels 46 16 are glued on at their upper and lower ends so that they are in the desired position the corresponding upper and lower rings 14 are fixed and the possibility of leakage from in connection. Gas or liquid is largely excluded.

The ribs 16 also preferably consist of a flexible expansion or sealing plate 50 made of metal,

made of plywood and are laid out lengthways, 35 plastic or wood veneer covers the inside

curved according to the shape of the container. As in Fig. 2 surface of the strip 48 and is on its edges

As shown, the ribs 16 are attached to the corresponding one by means of an adhesive against the adjacent ones

Ring 12 each fastened with the aid of two bolts 26 to seal plates 28. In the middle part of the plate 50

To increase the strength of the frame in addition, a bulge 52 is arranged through which the

and the rings 14 opposite the rings 12 in the 40 lateral expansion and contraction of the

to hold the desired position. Furthermore, the sealing plate 50 rests as a result of the movements of the corresponding

End portion of each rib 16 on the protruding part 18 corresponding plates 28 is facilitated. In the after

of the corresponding ring 12, so that this inwardly facing surface of the strip 48 is a

protruding shoulder-like part incorporated the frame in groove 54, in which the bulge 52

additionally supported in the vertical direction. 45 protrudes so that the strip 48 does the movements

On the inside of the frame, insulating plates of the plate 50 are not obstructed. There is also a slot

28 (Fig. 1) with closely spaced sides 56 cut into the strip 48 to lateral

edges attached so that there is a closed expansion and contraction of the strip

Storage space 30 results. The plates 28 (see FIG. 3) relative movements of the plates 28 towards one another

are preferably made of wood, with the inner 50 making it easier.

and outer panels 31 and 32 made of hardwood As the outer surfaces of panels 28 of the

and with the panels 31 and 32 exposed to ambient temperature, make themselves

relatively thick layer of an insulating material all expansions and combinations

of low density, sufficient strength and draws substantially close to the inner ones

Dimensional accuracy, such as balsa wood, quippo wood or 55 surface of the panels noticeable. Still it is

one made of paper or corrugated veneer advisable to have further grooves 58 in the butting

Honeycomb structure is arranged. The panels 31 and 32 edges the panels 28, from the bevels 46

are glued to the insulating layer 34. Due to the location on the outside, to attach which

this training retain the walls of the memory sealing strip such. B. rubber strip 60,

Raums 30 take their shape even with constant temperature 60 to avoid leaks and convection currents

changes, and to prevent the insulation forming the space 30 at the joints between the panels,

tion forms together with the frame a self- The storage space 30 is covered with a thin film

carrying container which does not have any support of the lined, which is loose on the floor and to the

Insulation needed on the inner surface. Side walls. The liner 62 is after

According to FIG. 3, the plates 28 are open at the top by means of the plan 65. It consists of gas and liquid skins 36 attached to the ribs 16, the planks being impermeable material and so thin that they with the help of bolts 38 on the inner edge is not self-supporting. The undressing can be advantageous Ribs are attached. The inward-facing manure 62 with an essentially round bottom

plate 64 be provided, which like the rest of the metal lining, such as. B. aluminum, aluminum alloy, Copper, stainless steel or other austenitic steel and on the outer circumference of which sheets made of the same metal are attached, along the inside of the Insulating plates 28 extend upwards. However, it is also possible to make the lining from a continuous Plastic film such as polyethylene, polytetrafluoroethylene or a layer of glass.

The metal sheets 66 forming the side walls of the lining 62 are advantageously made according to that shown in FIG. 4 Way connected. For this purpose, the edge 68 of the one sheet 66 is facing inwards Storage space 30 bent open. The corresponding edge 70 of the adjacent sheet 66 is also bent inwards and then flanged over the edge of the former sheet metal. The edges 68 and 70 are welded, soldered or pressed together, with or without sealant can be. This arrangement creates a number of distributed over the circumference of the container and bulges running from top to bottom, which are designated in the drawing by 72, which compensate for the expansion and contraction of the liner 62 in the circumferential direction. There the lining 62 is not firmly connected to the insulating plates 28, it can be independent of the Contract and expand insulation. This is especially important when the lining is made Aluminum or stainless steel and consequently contracts by larger amounts or expands as the insulating plates 28.

Preferably, a correspondingly formed groove 76 formed in the inner surfaces of the plates 28 is arranged opposite each of the bulges 72, a strip 74 is inserted, which is made of wood, such as balsa wood, can exist. Each of these strips 74 protrudes inwardly into the under the corresponding bulge 72 existing cavity and thereby prevents rotation or displacement of the liner 62 in the circumferential direction. The strips 74 are not attached to the liner 62 so that they Do not hinder movements of the bulges 72.

The lower ends 78 of the sheets 66 are preferably on the outer circumference of the plate 64 according to the in Fig. 5 attached manner shown and bent upwards, while at the same time the outer edge part 80 of the plate 64 is also bent up so that an angle is formed between the parts 78 and 80. The outer edge of the plate 64 is bent downwards and overlaps the end 78 of the plate 66. Das End 78 and part 80 of plate 64 are welded or soldered together. Even with this one Training creates a bulge running around the circumference, which is designated by 82 in the drawing is. The bulge 82 allows expansions and contractions occurring in the radial direction of the plate 64 and takes at least a part of the expansion taking place in the vertical direction and contraction of the sheets 66 so that breakage of the liner 62 is avoided. The bulges 72, which run in a vertical direction at the connection points of the adjacent metal sheets 66, are welded to the bulge 82 running in the circumferential direction.

Further circumferential bulges in the plate 64 can be compared to the Bulge 82 can be arranged offset inward if it is a large container. A ledge 83 is in a corresponding groove 84 formed in the plates 28 at the bottom of the Storage space 30 and engages the bulge 82 to slide the plate 64 prevent and thereby center the lining 62 in the storage space 30. The bar 83 am The bottom of the tank 10 is aligned

ίο with the bulge 82 circular.

The upper ends of the sheets 66 (Fig. 6), which form the upper edge of the liner 62, are, for. B. attached by welding to an angle or L-shaped portion indicated generally at 86.

The bracket 86 is preferably made of stainless steel or aluminum. In the vertical one Flange 90 of angle 86 is a number of perpendicular and circumferential directions at a distance from one another arranged slots 88, in which the in radial Direction of a strip 94 attached to the inner circumference of the storage space 30 inwardly protruding Loosely engage bolt 92. The bar 94 is preferably made of hard wood and is with the relevant insulating plate 28 connected to form a fixed bearing for the bolts 92. The bolts serve as a second device, which in the event of failure of the actual holding device for the lining, which is described in detail below, prevents them from collapsing. the Slots 88 are so long that the angle 86 against the bolts 92 during normal Expansion and contraction of the liner 62 can move up or down.

The liner 62 (Fig. 1) is in the normal state by an upper spider 96 and two lower ones Spiders 98 prevented from collapsing. The upper spider 96 is preferably made of wood, around the expansion and contraction occurring as a result of temperature fluctuations to a minimum to restrict. It is formed from the inner rings 100 and 100 a (Fig. 7), which by means of a Number of arms 104 extending in the radial direction are connected to an outer ring 102. Of the Outer ring 102 is composed of straight sections made of wood, which are connected via U-shaped, also made of wood parts 106 are connected to each other, so that the diameter of the Outer ring 102 change and thus the expansion and contraction of the angle 86 at the top End of the liner 62 can adjust. The outer ring 102 lies below the upper flange 108 (Fig. 6) of the angle 86.

The inner ring 100 (FIG. 1) of the spider 96 hangs down by several in the storage space 30 cables 110 on the upper rings 12 and 14. The cables 110 pass through openings in the respective insulating plates 28. The cables 110 are tightly fitted in the openings to provide the insulation not to affect. It is recommended that the cables 110 be made of stainless steel or the like Manufacture material in order to limit their expansion and contraction as much as possible. the Arms 104 of the spider 96 extend curved downward from the outer ring 102 to the inner ring 100 and inside and, since they are made of wood, are exposed to stress in a radial direction acting force flexible.

As the liner 62 contracts, the top flange 108 of the angle 86 follows pulled down onto the outer ring 102 of the spider 96 so that the arms 104 bend slightly. These Movement increases the radially outward force exerted by arms 104 on the flange 90 of the angle 86 is applied, whereby it is ensured that the upper part of the liner 62 cannot collapse and fall inward into space 30. Once the liner 62 heats up and expands, the arms 104 move the outer ring 102 upward so that it is in contact with the Angle 86 remains and in turn prevents collapse of the upper part of the liner when the memory space 30 is empty.

"The lower spiders 98 are formed in the same way as the upper spider 96, only with the The difference is that the arms of the lower spiders 98 are outwardly and downwardly from the inner to the outer Ring are bent. The material from which the spiders 98 are made must be of greater density than that of the stored liquid. The spiders 98 therefore dive into the one stored in space 30 Liquid in and press the outer rings constantly against the walls of the lining 62. The outer rings of the spiders 98 are suspended from cables 112 which extend from the angle 86. The tank 10 can be used to store a cold liquid, e.g. in the vicinity of a gas liquefaction plant, used or for the transport of such liquids in a means of transport, e.g. a ship. In the case of a stationary installation, the lower base ring 12 can be placed on foundations 114, as shown in FIG. 1, make up most of the tank weight and weight of the liquid content. Additional supports can be in the form of wood existing struts 116 are provided, which, starting from foundations 118, with the ribs 16 stay in contact. The struts 116 increase the stability of the tank and ensure that it does not tip over even in strong winds. If the tank is of considerable size, the lower ring is preferably reinforced by a number of transverse ties 120, which the Support plates 28 in the lower middle part of the tank. The binders 120 rest with their ends the protruding part 20 of the base ring 12. Additional foundations 122 can be arranged as required. It is also advisable to use a number of metal straps 124 to place one on top of the other around the ribs 16 in order to place them in the desired position to keep on the circumference of the tank and also to increase its strength in the radial direction.

If part of the tank insulation fails and the tank contents heat up, the pressure can suddenly rise in the room 30 so that normal safety valves are not sufficient to the increased Relieve pressure. It is therefore advisable to have a conical cover 126 that is aligned with the opening in the upper ring 14 covers to be provided in one of the upper insulating plates 28. The lid 126 normally forms part of the isolation. As soon as excessive pressure develops in space 30, the Lid 126 is thrown upward through the top rings 14 and 12 without damaging the tank will.

In Fig. 8 another embodiment of the invention is shown in which the tank as a whole is designated 210. The tank has a base ring 212 which rests on foundations 214. The base ring 212 is preferably made of layered wood and is set off near the outer perimeter, so that a shoulder 216 is formed. Typically, ring 212 is circular in shape, but it is also possible to use it in any other desired form,

ίο z. B. as an oval or polygon, especially as an octagon, to train. The bottom 218 of the tank 210 rests on top of the ring 212 and is preferably made from a number of insulating wooden panels that run diagonally to the ring 212. Each of the The panels forming the floor 218 are preferably larger with a layer of insulating wood 220 Provided starch, which is covered on the upper and lower outer surface with panels 222 made of hardwood. The insulating wood layer 220 can e.g. B. from balsa

ao or Quippo wood, and the panels 222 can be made of hard plywood. The floor 218 is additionally supported by foundations 224 and Wooden inlays 226 supported.

The side walls of the tank 210 consist of vertically arranged insulating panels 228 which are attached to the Connect the outer circumference of the bottom 218. The lower end of each of the panels 228 is at 230 correspondingly the shoulder 216 on the ring 212 leaved. Further, the lower end portions of the panels are 228 by means of projections 232 which engage the panels 228 and the ends of the panels forming the bottom 218, attached to the outer periphery of the bottom 218. A seal (not shown) can be placed between the contacting surfaces of the vertically arranged panels 228 and the floor 218 should be attached.

The panels 228 are self-supporting. The panels 228 are in the same way as those forming the floor 218 Panels formed (Fig. 9). They consist of a relatively thick layer 234 of insulating Wood, such as B. balsa or quippo wood, and hardwood panels 236, the inside and outside of the Cover layer 234. It is also advisable to put a strip 238 of hardwood on each side edge of the To attach panels 228 that extends the full length of the panel, with the outer surface this strip 238 is flattened from the inside of the panels. The flats 240 of the neighboring Strips 238 run in the opposite direction so that a groove for receiving a corresponding trained bar 242 made of relatively soft wood, for. B. balsa wood is formed. Each ledge 242 extends the length of the panels 228 and is in the corresponding flat 240 clamped to create an effective seal between adjacent panels 228 and at the same time to create an expansion possibility. It is also preferable to have a weather strip 244 to attach made of rubber.

The vertically extending panels 228 are formed by spaced apart bands 246 held together. The bands 246 can be made of metal, e.g. B. steel, exist as they are not essential Are exposed to temperature fluctuations. The straps 246 are fixed to the outer surfaces of the Panels 228 attached adjacent. In order to ensure that the panels 228 the on them by the Belts withstand 246 stresses exerted

hold, hardwood is placed in each panel 228 under the belts 246. The deposits 248 form a additional reinforcement at the points of the panels in contact with the retaining straps 246. It it is also advisable to attach hardwood inserts 250 to the top and bottom of panels 228 where these are in contact with the base ring 212 and the cover 252. The hardwood inlays 250 on the lower ends of the panels 228 ensure that the panels are not damaged. The hardwood inlays 250 at both the top and bottom also form a protection for the insulating wood in the boards against adverse weather conditions.

The lid 252 can be formed in any manner, e.g. B. as a half-timbered vault, which consists of a base part 254 and a number of arched ties 256. The base part 254 and the ties 256 can be made of wood. It is advisable to cover the top of the lid 252 with a sheet of metal to be used as protection against rain and snow. The lining 258 is preferably made of aluminum. Of the Cover 252 is tightly spaced with the help of insulating plates 260, which are under the bottom of the base part 254 are attached, isolated. The plates 260 close to the inner surfaces in the vertical direction extending panels 228, the base portion 254 of the lid 252 having a larger diameter and rests on the tops of the panels 228. Again, it is advisable to use seals between the contacting surfaces of the base part 254 of the lid and the to attach upper ends of the panels 228.

A relatively thin liner 262, like those previously described, consists of one Base plate 264 and side panels 266. Base plate 264 has at least one circumferential Bulge 268 is provided to accommodate the expansion and contraction of the plate. The base plate 264 is in turn secured against displacement with respect to the floor 218 by means of strips and centered at the same time. Bars of any shape can be used for this purpose, such as B. such of square cross-section in the center of plate 264. However, it is preferable to have a bulge 268 or a similar one to that shown in FIG. 3 for fastening the plate 264 with respect to the floor 218 to use. The bulge 268 is downwardly directed and fits loosely into a circumferential one Groove 270 formed in the surface of a ring 272, e.g. B. made of balsa wood, is arranged. The ring 272 in turn lies in a circumferential groove 274 machined in the upper surface of the base 218.

As shown in Figure 8, the lower edge of the lowermost panel 266 is on the outer periphery of the base plate 264 welded or soldered to create a gas- and liquid-tight connection of the lower panel 266 with the base plate. This lower panel extends on the inside of the vertically standing panels 228 upwards and is welded at its upper end to a ring 276 or soldered, which is preferably made of stainless steel and has a T-shaped cross-section. The upper edge of the lower panel 266 is welded to the downwardly facing flange of the ring 276, while the lower edge of the next upper panel 266 to the upward flange of the ring 276 is welded on. The remaining panels 266 are by means of the rings, which are T-shaped in cross-section 276 connected in the same way to complete the liner 262. A ring 276 (Fig. 8) is attached to the top edge of the top panel 266 and the top panel 266 terminates in one a short distance below the top of the vertical panels 228. Beyond that is each panel 266 with an inwardly projecting, circumferentially disposed bulge 278 in its central part, which the expansion and contraction of the panel 266 in vertical Takes up direction without significant movements of the rings 276 in the vertical direction, as previously described.

The liner 262 is prevented from collapsing by a support structure consisting of a Number of vertically stacked wooden rings 282 consists of vertically arranged wooden columns 284 are worn. Each ring 282 is preferably made of laminated wood and is with

ao provided on the outer periphery of a groove 286 (Fig. 11) which is dimensioned so that it is slidable the horizontally protruding flange portion of one of the rings 276 of the liner 262 can receive. A ring 276 is provided for each of the rings 282

as and rings 276 are sized to loosely fit into the liner 262 will fit in when it contracts to its smallest diameter Has. The horizontally protruding flange part of the rings 276 and the grooves 286 are so long that that the ring 276 remains in the associated groove 286 when the diameter of the liner 262 increases or decreases as a result of expansion or contraction, the rings 276 maintaining their position, although they can slide freely into or out of the grooves 286. Provided it is desired that a balsa wood insert 287 may be placed inside each groove 286, as shown in FIG is to be attached to the force exerted on the rings 276 in the event that the rings 276 be excessively contracted to accommodate. It can also be seen (Fig. 8) that each pair Rings 276 and 282 the retaining straps 246 spanning the panels 228 and thus also the hardwood inlays 248 located in the panels 228 to ensure that the Panels 228 are not damaged if the rings 276 contract excessively.

The support pillars 284 are preferably made of laminated wood and are as shown in FIGS is provided with recesses 288 arranged at a distance from one another in the vertical direction, which serve to receive the support rings 282 and to hold them in the required position. Of the Structure made of layered wood ensures the greatest possible flexural strength of the supporting structure 280. The vertical columns 284 are additionally supported by inclined struts 290, which are also made of layered Made of wood and with the help of consoles (not shown) z. B. made of stainless Steel are attached to the associated pillars 284. Also at the lower end of the liner is 262 a support ring 282 is attached, which is a base for the support structure 280 and a warping the lower part of the lining.

As can be seen from FIG. 8, the insulating plates attached to the underside of the cover 252 protrude 260 outwards over the uppermost support ring 282

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and can be carried by this ring with the aid of an insulating pad 292 therebetween.

Claims (6)

PATENT CLAIMS: 1. Storage tank for the storage of liquefied gases at normal pressure and low temperatures, consisting of a arranged within a jacket of heat-insulating material, at least partially adjacent to this jacket lining made of a thin flexible film of a liquid-tight, non-self-supporting material, characterized in that the according to liner (62; 262) open at the top is supported by means of horizontally arranged annular parts (96, 98; 276, 282) which are connected to the inside of the liner at its upper end and at one or more points between the upper end and the base plate (64 ; 264) of the liner, the annular parts being suspended in the upper part of the container or supported in the lower part of the container. 2. Storage tank according to claim 1, characterized in that the annular parts consist of horizontally arranged spiders (96, 98) which are connected to one another by cables (112) and attached to the top of the tank (10) by cables (110) . 3. Storage tank according to claim 2, characterized in that the spiders have an outer ring (102) and an inner ring (100) which are connected to one another by radial arms (104). 4. Storage tank according to claim 3, characterized in that the inner ring (100) of the uppermost spider (96) is attached to the top of the tank (10) by cables (110) , and the outer rings (102) of the spiders (96, 98 ) are interconnected by cables (112). 5. Storage tank according to claim 1, characterized in that the annular parts consist of T-shaped rings (276) , on the flanges of which the lining (262) is attached, while the webs are slidable in horizontal grooves (286) of further rings (282) are fitted, which are supported on a support structure (280) on the bottom of the container. 6. Storage tank according to claims 1 and 5, characterized in that the base plate (264) is provided with one or more bulges (268) which extend in a preferably in a wooden ring (272) made groove (270) which is in the heat insulating material (220) is embedded. Considered publications:
U.S. Patent No. 2,393,964. For this purpose 2 sheets of drawings © 309 767/91 11.63