GB1567789A

GB1567789A - Compartmentalised tanks

Info

Publication number: GB1567789A
Application number: GB76177A
Authority: GB
Original assignee: MURGUE SEIGLE
Current assignee: MURGUE SEIGLE
Priority date: 1976-01-27
Filing date: 1977-01-10
Publication date: 1980-05-21
Also published as: DE2703362A1; FR2339548B1; JPS5292119A; BE850223A; IT1116694B; FR2339548A1

Description

(54) IMPROVEMENTS IN OR RELATING TO COMPARTMENTALISED TANKS (71) We, MURGE-SEIGLB, a Societe Anonyme organised under thelaws of France of 15, Avenue A. Einstein, 69 Villeurbanne, France, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a com parttnentaiised tank designed in particular for the transport of hydrocarbons.

Conventional tanks are made up of several basic units which are fixed to the inner wall of an outer skin of cylindrical shape so as to divide it into separate compartments. Where the tank is made from reinforced plastics material, each basic unit usually is the shape of a bowl of uniform thickness the outer skirt of which is positioned as desired on the outer skin by driving in and rotating true unit through 90 .

In tanks Of this type, the basic elements merely fonm simple bulkheads which make lie oontribution to the overall strength of the tank. The attachment of the various skirts to the inner wall of the tank also causes abrupt variations in thickness of the tank wall which variations are prejudicial to the distribution of strains to which the tank is likely to he subjected. Further, it is necessary to provide a prefabricated gland or collar in the acute angle formed between each skirt and the outer wall of the convex side of the base-element so as to prevent the accumulation of dirt in the angle to which faces is difficult. A band is also required to cover the end of the skirt after sticking in order to obtain staunchness and rigidity.

The object of the present invention is to ptsvidle a tank in which the abovementioned s vbacks are obviated or substantially mitigated.

According to the present invention there is provided a compartmentalised tank in clxLing a tabular wall, two end pieces and at least one partition attached to the inner surface of the wall to subdivide the tank into distinct compartments, each partition comprising a central portion arranged trans tersely to the wall of the tank and a sub stanial1y tubular peripheral portion which is attached to the inner wall surface of the tank and which joins the central portion along smoothly curved surfaces to extend along the tank wall on either side of the central portion, and at least one sleeve fixed tightly to the inner wall surface of the tank and separting either one of the end pieces and a partition from each other or two partitions from each other.

The arrangement of the curved surfaces between the central and peripheral parts of each partition produces a strengthening effect within the tank and assists in the distribution of the stresses. These surfaces also avoid sharp corners which would be difficult or impossible to reach when the tank-com- partments are cleaned.

Each of the sleeves prevent excessively abrupt variations of thickness of the tank wall and the mechanical behaviour of the tank is improved. Each sleeve allows an exact determination of the distance between two neighbouring partitions or end-pieces and thereby, the internal volume of each compartment. Further, the sleeves should be made of a material with a high degree of resistance to chemical corrosion but can be of only average mechanical strength, the outer skin of the tank itself being made perhaps of different material having but limited resistance to corrosion by atmospheric conditions.

In one preferred embodiment each partition or end-piece is made of plastics material which may have an internal rein- forcement composed either of resin mixed with tiny balls or of a cellular structure.

According to a further aspect of the present invention there is provided a method of making a compartmentalised tank comprising the steps of manufacturing two end pieces and at least one partition each of similar construction and having a central portion and a substantially tubular peripheral portion joining the central portion along smoothly curved surfaces and with rebated portions on the axially directed edges which project on either side of the central portion, assembling the end-pieces and each partition together by interposing prefabricated sleeves of predetermined length between them, which sleeves are slid into the rebated portions in each neighbouring partition or end-piece, and tightly fixing an outer tubular wall around the outer wall surface of the sleeve and adjoining wall surfaces of the end-pieces and each partition.

The invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a cross-section of part of a tank with several compartments according to the present invention; Figure 2 is a cross-section to a larger scale of part of the tank shown in Fig. 1; and Figure 3 is a cross-sectional view similar to Fig. 2 showing an alternative arrangement.

In the drawing, reference 10 designates a compartmentalised tank for the shipment of hydrocarbons.

The tank 10 of which only part is shown in Fig. 1 comprises an outer skin 12 of tubular cylindrical shape with a circular base. Each endpiece 14 is arranged on and fixed to the two ends of the skin 12, and an intermediate partition 16 is suitably fixed inside the skin so as to divide up the volume of the tank 10 into separate compartments 18a and 18b. The partition 16 can either hermetically separate two neighbouring compartments of the tank 10 or simply divide a compartment into auxiliary compartments inter-connected by a suitable opening so dividing up the mass of fluid contained within the tank 10 while allowing its passage from one side of the tank to the other.

The term 'compartment' as used in this application includes any space within the tank 10 bounded by two successive partitions or "breakwaters" or by two hermetically sealed partitions, or any combination thereof.

As described and shown in the drawing, the end piece and partition 14 and 16 are of similar shape. However it is envisaged that in some embodiments of the invention the end pieces 14 and the partitions 16 would be of different shape.

In the present embodiment each end piece 14 and the partition 16 comprises a central portion 20, which extends across the cylindrical inner surface 22 of the shell 12, and a peripheral portion 24, of substantially tubular shape, the outer surface 26 of which follows closely the shape of the skin 12 to which it is fixed as explained below. The central part 28 of the peripheral portion 24 joins the edge of the central portion 20 with two cnrves 30 and 32. which can be of equal or differing radius. These curves 30 and 32 assist the peripheral portion 24 to form a stiffening-ring for strengthening the shell 12 at the region level of the partition or end piece.

The central portion 20 may advantageously be of variable thickness and comprise a meniscus such as that of a divergent meniscus as shown in figures 1 and 2 or a convergent meniscus as shown in figure 3; the opposing faces 34 and 36 of this central portion being in these cases convex and ooncave. It will be understood, however, that any other shape could be adopted according to the stresses to which the tank is to be subjected. Thus, in the case of storage at high pressure, the shape of the portion or end piece will be preferably that of a divergent meniscus as shown in figures 1 and 2 while for low pressures a convergent meniscus as shown in figure 3 would be preferable.

By judicious selection of the curvature and variation of the thickness of the end-pieces 14 and partitions 16, deformation of the tank 10 can be reduced and its rigidity increased.

The axially directed edges or outer surface 26 of each end piece 14 and partition 16 has at its end two cylindrical rebated portions 38 and 40 of the same radial depth so as to allow a sleeve 42 to slide onto these offsets, the sleeve being of constant thickness and having a depth equal to that of the offsets. The outer surface 44 of the sleeve 42 is fixed, as explained below, to the inner face 22 of skin 12.

Each sleeve 42 is designed to give a degree of continuity to the walls of the tank-com- partments 18a and 18b. Being attached closely to the skin 12, it prevents abrupt variation in the thickness of the tank walls owing to the insertion of partitions 16 or end-pieces 14. Further, by thrusting against the annular shoulders 46 and 48, formed by the offset portions 38 and 40 respectively, each sleeve 42 can ensure precise relative location of successive partitions 16 and endpieces 14 and thereby determine the exact internal volume of the compartment 18 thus bonded.

One possible method of fabricating the tank will be described below Firstly, the various end-pieces and partitions 14 and 16 are manufactured of preferably a plastics material as necessary for dividing up the tank according to the number of compartments 18 required. Secondly, sleeves 42 are slid around the offset portions 38 and 40 of the end pieces 14 and the partitions 16. These sleeves 42 may be made by cutting up a tube into appropriate lengths.

This tube can be made, for example, by winding bands or threads of glass fibre impregnated with a suitable resin which can be hardened by heating in accordance with a known technique. Naturally, the material from which the sleeves are made should have a high degree of resistance to corrosion by fluids, both liquids and gases. which are to be stored in each compartment 18.

The sleeve 42 can be welded or bonded ont the offsets 318 and 40 and once this is accomplished, the cylindrical assembly obtained can be covered with the skin 12. This latter should be made from a material having good mechanical properties so as to be capable of absorbing, in conjunction with the end-pieces 14 and the partitions 16, the stresses to which the tank 10 is likely to be rjeotead.

In a preferred embodiment, the skin 12 is made by crossed windings of bands or threads of glassdibre impregnated with hot dening resin of an appropriate type. This winding is carried out directly on the core, which is formed by the end pieces 14, partitions 16 and the sleeves 42, and gives a highly bomogeneous structure, the various parts of the tank 10 being held together by the outer skin 12 itself, and ensures a good distribution' of stresses and thereby good mechanical performance of the tank 10.

Each Of the end-pieces 14 or partitions 16 can be obtained by one of the methods des cried below.

In a first method two walls of concave shape are made by contact-layering, that is by application upon a form of a cloth or mat of glass-fibre impregnated with heathardening resin. These walls are designed to form the opposite faces 34 and 36 of the end-piece or partition. Each wall has a skirt on its periphery turned, in one case, in the direction of the concavity of the wall face as with 36 shown in figure 2, and, in the other case, in the opposite direction as with face 34 in the same figure. These two walls are then bonded together in a press and arranged back to back upon a prefabricated cylindrical sleeve-element designed to form the outer surface 26.Interposed between the walls is a preffhaped filling made from cellular material or impregnated felt so as to give a sandwich-type structure. The two walls are only partly sunk into the sleeveelement so as to create the cylindrical offsets 38 and 40.

A preferred method is, however, a moulding-method which consists of injecting into a mould of suitable shape corresponding to that of the end piece or partition required, an appropriate resin such as a polyester.

Taking into account the thickness of the m'oulding, it is an advantage to arrange in the mould, before injection of the resin, a core made of either a moulded resin charged with inert micro balls or a light material having mechanical properties such as a high resistance to shear and oompression. In the former case, the charge used, for example, could be micro-balls of a phenol-base, or d glass or tiny balls of a substance known comercially as 'SARAN' which is a copolymer of thermoplastic vinylidene chloride (acrylonitrile). In the latter case, the core can be made out of a cellular material, moulded into shape or cut out.For example, one could use a polyurethane foam, or balsa wood, or expanded polystryene, or a phenolic foam, again one could use a honeycomb structure made from cardboard impregnated or otherwise with resin or aluminium, or again one could use an upright wooden shape. One could also make a core for the mould, prior to the injection of the resin, from a suitable material such as expanded glass or better still from strips of felt charged with micro-balls.

WHAT WE CLAIM IS:- 1. A compartmentalised tank including a tubular wall, two end-pieces and at least one partition attached to the inner surface of the wall to sub-divide the tank into distinct compartments, each partition comprising a central portion arranged transversely to the wall of the tank and a substantially tubular peripheral portion which is attached to the inner wall surface of the tank and which joins the central portion along smoothly curved surfaces to extend along the tank wall on either side of the central portion, and at least one sleeve fixed tightly to the inner wall surface of the tank and separating either one of the end-pieces and a partition from each other or two partitions from each other.

2. A tank as claimed in claim 1, in which the end of each sleeve can slide into a rebated portion in the axially directed edges of the adjacent end-piece or partition.

3. A tank as claimed in claim 1 or 2, in which the central portion of each partition comprises a meniscus shape of a predetermined thickness so as to provide a strengthening of the central portion, 4. A tank as claimed in claim 3, in which the central portion has opposed faces of which one is convex and the other is concave.

5. A tank as claimed in any one of claims 1 to 4, in which the two end-pieces are of similar construction to the partition of the tank.

6. A tank as claimed in any one of claims 1 to 5, in which each end-piece or partition is made of a plastics material which may incorporate a core made either of a resin moulding mixed with micro-spheres or be of a cellular structure.

7. A tank as claimed in any preceding claim in which the wall of the tank is made of a reinforced plastics material.

8. A method of making a compartmentalised tank as claimed in claim 2, comprising the steps of manufacturing two endpieces and at least one partition each of similar construction and having a central portion and a substantially tubular peripheral portion joining the central portion along smoothly curved surfaces and with rebated portions on the axially directed edges which project on either side of the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. accomplished, the cylindrical assembly obtained can be covered with the skin 12. This latter should be made from a material having good mechanical properties so as to be capable of absorbing, in conjunction with the end-pieces 14 and the partitions 16, the stresses to which the tank 10 is likely to be rjeotead. In a preferred embodiment, the skin 12 is made by crossed windings of bands or threads of glassdibre impregnated with hot dening resin of an appropriate type. This winding is carried out directly on the core, which is formed by the end pieces 14, partitions 16 and the sleeves 42, and gives a highly bomogeneous structure, the various parts of the tank 10 being held together by the outer skin 12 itself, and ensures a good distribution' of stresses and thereby good mechanical performance of the tank 10. Each Of the end-pieces 14 or partitions 16 can be obtained by one of the methods des cried below. In a first method two walls of concave shape are made by contact-layering, that is by application upon a form of a cloth or mat of glass-fibre impregnated with heathardening resin. These walls are designed to form the opposite faces 34 and 36 of the end-piece or partition. Each wall has a skirt on its periphery turned, in one case, in the direction of the concavity of the wall face as with 36 shown in figure 2, and, in the other case, in the opposite direction as with face 34 in the same figure. These two walls are then bonded together in a press and arranged back to back upon a prefabricated cylindrical sleeve-element designed to form the outer surface 26.Interposed between the walls is a preffhaped filling made from cellular material or impregnated felt so as to give a sandwich-type structure. The two walls are only partly sunk into the sleeveelement so as to create the cylindrical offsets 38 and 40. A preferred method is, however, a moulding-method which consists of injecting into a mould of suitable shape corresponding to that of the end piece or partition required, an appropriate resin such as a polyester. Taking into account the thickness of the m'oulding, it is an advantage to arrange in the mould, before injection of the resin, a core made of either a moulded resin charged with inert micro balls or a light material having mechanical properties such as a high resistance to shear and oompression. In the former case, the charge used, for example, could be micro-balls of a phenol-base, or d glass or tiny balls of a substance known comercially as 'SARAN' which is a copolymer of thermoplastic vinylidene chloride (acrylonitrile). In the latter case, the core can be made out of a cellular material, moulded into shape or cut out.For example, one could use a polyurethane foam, or balsa wood, or expanded polystryene, or a phenolic foam, again one could use a honeycomb structure made from cardboard impregnated or otherwise with resin or aluminium, or again one could use an upright wooden shape. One could also make a core for the mould, prior to the injection of the resin, from a suitable material such as expanded glass or better still from strips of felt charged with micro-balls. WHAT WE CLAIM IS:-

1. A compartmentalised tank including a tubular wall, two end-pieces and at least one partition attached to the inner surface of the wall to sub-divide the tank into distinct compartments, each partition comprising a central portion arranged transversely to the wall of the tank and a substantially tubular peripheral portion which is attached to the inner wall surface of the tank and which joins the central portion along smoothly curved surfaces to extend along the tank wall on either side of the central portion, and at least one sleeve fixed tightly to the inner wall surface of the tank and separating either one of the end-pieces and a partition from each other or two partitions from each other.

3. A tank as claimed in claim 1 or 2, in which the central portion of each partition comprises a meniscus shape of a predetermined thickness so as to provide a strengthening of the central portion,

4. A tank as claimed in claim 3, in which the central portion has opposed faces of which one is convex and the other is concave.

central portion, assembling the end-pieces and each partition together by interposing prefabricated sleeves of predetermined length between them, which sleeves are slid into the rebated portions in each neighbouring partition or end-piece, and tightly fixing an outer tubular wall around the outer wall surface of the sleeve and adjoining wall surfaces of the end-pieces, and each partition.

9. A method as claimed in claim 8, in which the tubular wall is produced by winding fibres or bands impregnated with resin onto the outside of the assembly made by the sleeve, end pieces and each partition.

10. A method as claimed in claim 8 or 9, in which the end-pieces andlor each partition is made by injecting a synthetic resin into a mould of appropriate shape.

11. A method as claimed in claim 10, in which a core is placed in the mould before injection of the resin.

12. A method as claimed in claim 11, in which the core is made of a resin moulding mixed with mioro-spheres.

13. A method as claimed in claim 11, in which the core is of a pre-formed cellular structure.

14. A method as claimed in claim 11, in which the core comprises at least one thickness of felt whith micro-spheres.

15. A method as claimed in claim 8 or 9 in which each end piece or partition is manufactured by making two walls from reinforced resin, each wall having a peripheral skirt, and assembling the two walls together by positioning same back to back and partially sinking the skirts of these walls into an outer sleeve element.

16. A method as claimed in claim 15, in which the core is fitted and bonded between the two walls so as to produce a sandwich construction.

17. A compartmentalised tank made by the method as claimed in any of claims 8 to 16.

18. A c'ompartmentalised tank sub tank tially as hereinbefore described with reference to Fig. 1 of the accompanying drawing.