WO1998013276A1

WO1998013276A1 - Collapsible fluid vessels

Info

Publication number: WO1998013276A1
Application number: PCT/GB1997/002585
Authority: WO
Inventors: Stephen Anthony Stafford
Original assignee: Stephen Anthony Stafford
Priority date: 1996-09-26
Filing date: 1997-09-23
Publication date: 1998-04-02
Also published as: GB9620023D0; AU4313597A

Abstract

A collapsible vessel for the storage and transport of liquids comprises a protective outer bag (25) made from stitched woven fabric and an inner lining bag (24) made from a flexible liquid-impermeable sheet material. Flow duct means (10, 12) opening into the inner bag (24) permit filling thereof with liquid from outside the outer bag (25) for storage and transport and subsequent emptying thereof. The outer bag (25) may further be provided with a generally lightweight and low-strength covering of polythene to act as a bearing surface between the outer bag (25) and the inside of a conventional transportable container in order to minimise or eliminate abrasion of the outer bag (25) during transport of liquids.

Description

"Collapsible Fluid Vessels"

This invention relates to collapsible vessels for storage and transport of liquids

Collapsible vessels known as flexitanks are widely used to contain bulk liquids

so as to enable them to be transported or stored in standard ISO shipping containers of

the type used for shipping dry products Such flexitanks have the advantage that, after

they have been used for transporting a liquid product to a particular destination and after

emptying of the product, the flexitank can be collapsed and shipped back to its point of

origin for re-use at relatively low cost in view of the small space occupied by the

collapsed flexitank .Mternatively the flexitank can simply be disposed of if it is of a type

intended to be used only once thus avoiding the need for cleaning prior to re-use

Early flexitanks were made from rubber coated fabrics However more recently

flexitanks have been constructed from fabπcs coated with thermoplastics materials such

as polyvinyl chloride (PVC) and polyurethane Disposable flexitanks have been

produced using lightweight PVC coated fabrics However the use of such lightweight

PVC coated fabrics presents a number of problems Firstly, recent environmental

legislation makes it difficult to dispose of such flexitanks, and in addition such flexitanks

cannot be recycled because the fabric and the PVC coating cannot easily be separated

Furthermore, in order to keep the cost of such flexitanks to a minimum, the PVC coating

is very thin and this makes the flexitank vulnerable to damage from abrasion whilst in transit and increases the risk of leakage Also such flexitanks are not suitable for

transporting hydrocarbons such as lubricating oils

It is an object of the invention to provide an improved collapsible vessel for the

storage and transport of liquids

The invention is defined by the accompanying claims

The fabric outer bag of such a flexitank

be produced so as to impart strength

and resistance to abrasion whilst the inner bag is used to contain the liquid As a result

the flexitank may be produced as a low cost disposable item or a low cost reusable item

Furthermore, the inner and outer bags can be separated easily for recycling and the

flexitank may be of light weight so that low transportation costs are incurred for

shipping of the flexitank when empty Furthermoi e the inner bag can be manufactured

in a sterile environment so as to be aseptic and so that it does not require sterilisation

before use with food products such as wine

In a further embodiment of the invention the outer bag is made of nylon so as to

impart greater strength thereto than would otherwise be the case by the use of, for

example, a polypropylene fabric Preferably, the outer bag is itself contained within a

generally lightweight and low-strength covering which may be one piece or be

comprised of several pieces of polythene intended solely to act as a bearing surface between the outer bag and the inside of a container in order to minimise or completely

eliminate abrasion of the outer bag during transport of liquids

In a further embodiment of the invention, the outer bag may be comprised of two

or more layers of woven material with alternating or angularly displaced directions of

weave so as to maximise the strength thereof and minimise the risk of rupture of the

layers at a single point such as would or could occui if the direction of weave for each

layer were to be identical

In a further embodiment of the invention the outer bag may be made from a tube

of woven material stitched at each end foi closure thereof and optionally including

reinforcement means such as plastics clips or beading along the stitch lines at each end

such that, effectively, rupture of the bag and leakage of liquid could only occur at such

points, thereby minimising the number of possible sites for such to occur

In a further alternative embodiment the outer bag is made from a tube

constructed of a single sheet of woven material folded in on itself and stitched

lengthwise and at each end with, optionally, further reinforcement means being provided

along the lines of stitching in the manner as described above

In order that the invention may be more fully understood, reference will now be

made, by way of example, to the accompanying drawings, in which'

Figure 1 is a diagrammatic perspective view of a collapsed flexitank according to the invention within a shipping container,

Figures 2 and 3 are perspective and sectional views of a filling/emptying hose

assembly of the flexitank,

Figures 4 and 5 are perspective and sectional views of a vent assembly of the

flexitank,

Figure 6 is a detail showing a section through a collar welded to the inner bag

of the flexitank.

Figure 7 is a perspective view of the mnei bag removed from the flexitank,

Figure 8 is a diagrammatic sectional \ le of a furthei possible flexitank in

accordance with the invention,

Figures 9, 10 and 1 1 are perspective views of a further possible flexitank

according to the invention; and

Figures 12 and 13 are perspective views illustrating the fitting of a bulkhead

within a shipping container for containing the flexitank

The illustrated flexitank in accordance with the invention in this example

comprises a protective outer bag made from fabric which has been woven from fibres

of polypropylene and which has been subsequently coated with a layer of polypropylene

on at least one side so as to render the fabric substantially liquid-impermeable.

Furthermore an inner lining bag made from polythene sheet material is secured within

the outer bag by stitching in a manner which will be described in more detail below. As

shown diagrammatically in Figure 1 the flexitank 2 is secured within a standard 20 ft ISO shipping container 4 by means of a harness t> which is connected to connection points

8 within the container 4 in known manner Furthermore the flexitank 2 is provided with

a filling/emptying hose assembly 10 and a vent assembly 12, and a bulkhead 14 is

detachably locatable within one end of the container 4 so as to contain the flexitank 2

within the container 4 as it is being filled with liquid with one of the doors 16 of the

container 4 in the open position

As shown in Figure 2 the hose assembly 10 comprises a flexible intermediate

section 18 to which a suction stub fitting 19 and a hose end fitting 20 with cap 21 are

attached by means of clips 22 As shown diagrammaticallv in Figure 3, the suction stub

fitting 19 extends through a polythene sleeve 23 welded to the inner lining bag 24 and

drawn up through a flanged polypropylene sleeve 26 stitched to the outer bag 25 A

rubber collar 27 is positioned between the sleeves 23 and 26, and a worm-drive band

clamp 28 is applied to the outside of the outer sleeve 26 so as to clamp the fitting 19

within the inner sleeve 23, the rubber collar 27 serving to ensure a uniform damping

force sufficient to provide fluid-tight sealing between the outside of the fitting 19 and

the inside of the inner sleeve 23 The fitting of the vent assembly 12 may be effected in

similar manner

Alternatively the fitting of the hose assembly 10 or the vent assembly 12 may be

effected in a different manner, as will now be described with reference to Figures 4 and

5 showing the fitting of the vent assembly 12 The vent assembly 12 comprises a body 30 fitted with a screwthreaded cap 3 1 and having a screwthreaded end 32 which may be

engaged within an internally screwthreaded collar 33 welded to the inner lining bag 24

A rubber collar 27 is located between the outside of the vent body 30 and the inside of

the sleeve 26 stitched to the outer bag 25, and a clamp 28 is again used to secure the

assembly in position The fitting of the hose assembly 10 may be effected in similar

manner

As a further alternative both the ho^e assembly 10 and the vent assembly 12 may

be fitted in position by being secured within an lnteinalK screwthreaded collar 35 welded

to the inner lining bag 24, as shown in the detail of Figure 6, and extending through a

reinforced hole 36 in the outer bag 25 In this case the collar 35 passes through the

reinforced hole 36 loosely and is not secured therein in liquid-tight manner However,

in the event of a leak in the innei lining bag 24 resulting in spillage of liquid into the

outer bag 25, the outer bag 25 will still serve to contain the liquid provided that the

reinforced hole 36 is above the level of the liquid

Figure 7 shows the inner lining bag 24 provided with internally screwthreaded

collars 37 and 38 for fitting of the hose and vent assemblies and having flanges 39 along

its opposite edges permitting securing of the inner lining bag 24 within the outer bag by

stitching As will readily be appreciated from the detail of Figure 7A representing a

section taken along the line A-A in Figure 7, each flange 39 is formed by welding or

sticking two edges of folded strip reinforcing tape to opposite sides of the edge of the inner bag 24 so that stitches 41 passing through the flange 39 do not serve to puncture

the liquid-containing part of the inner bag 24 The stitching of the inner bag 24 within

the outer bag along the two opposite edges of the inner bag 24 is sufficient to correctly

locate the inner bag within the outer bag and prevent any folding of the inner bag in such

a manner as to obstruct complete filling of the inner bag However, if required, the inner

bag may also be stitched to the outer bag along one or both of its other edges In a

further variant, the flanges 39 may be formed integrally with the inner bag 24, for

example by welding the two sides of the inner bag 24 together along edge portions to

form the flanges 39

In a further possible variant flexitank 42 illustrated diagrammatically in section

in Figure 8, two inner lining bags 43 and 44 are arranged back-to-back within a single

outer bag 46 Each of the inner lining bags 43 and 44 is secured within the outer bag 46

by stitching 48 extending through the outer bag 46 and edge flanges 49 of each inner bag

43 or 44 in the manner already described It will be noted from this figure that the outer

bag 46 is formed by stitching together the peripheral edges of two fabric sheets, this also

being the way in which the outer bag 25 already described is formed The inner bags 43

or 44 are provided with respective collars 35, and the outer bag 46 is provided with

reinforced openings 36 on each side through which the associated collars 35 may be

passed for attaching a hose assembly or vent assembly thereto The collars 35 may be

fitted with blanking caps (not shown) when not connected to the hose and vent

assemblies A flap 50 is securable over the or each bottom opening 36 shown in the figure, for example by means of Velcro stπps, in order to protect the opening 36 and the

corresponding collar 35 when the flexitank 42 is resting on a flat surface with the

orientation shown

The inner lining bag 43 of the flexitank 42 may be filled with liquid after fitting

of a hose assembly to the collar 35 thereon, and also fitting of a vent assembly to a

similar collar (not shown) fitted to the inner bag 43 and the liquid may then be

transported to the intended destination within the inner bag 43 with the second inner bag

44 remaining empty and simply lying flat beneath the filled inner bag 43 during transport

Subsequently, after emptying of the inner bag 43 and detachment of the hose and vent

assemblies therefrom, the flexitank 42 may be turned the other way up and the inner bag

44 may then be filled with liquid after fitting of the hose and vent assemblies thereto (the

blanking caps being transferred to the collars 35 of the innei bag 43) The liquid

introduced into the inner bag 44 may then be ti ansported on the i eturn journey with the

inner bag 43 then remaining flat beneath the inner bag 44 Thus a single flexitank 42

may be used for transporting different liquids on the outward and return legs of a

journey without requiring cleaning of the inner bags and without contamination of either

liquid occurring The collars 35 are able to e flat on the underside of the flexitank 42

without causing any undue stress to the flexitank when the upper inner bag is full of

liquid and in transit

In a further variant flexitank 52 shown in Figui es 9 and 10 the inner lining bag 53 is removable through a reinforced access slit 55 in the outer bag 44 and is replaceable

by a fresh inner bag for each use After withdrawal of the old inner bag 53 through the

slit 55, as shown in Figure 10, and replacement by a fresh inner bag, a flap 56 is folded

over to cover the slit, as shown in the detail of Figure 9A, and a number of webbing

straps 57 are buckled together over the flap 56 prior to a second flap 58 being folded

over the straps 57, and possibly secured by Velcro strips in order to protect the straps

and their fastenings against abrasion in use

For securing of the inner lining bag 53 within the outer bag 54, the outer bag 54

is provided with eyelets 60 in its top and bottom surfaces at each corner and the inner

bag 53 is provided with pierced tabs 61 of reinforced tape at each corner After

insertion of the inner bag 53 within the outer bag 52, the corners of the inner bag 53 are

located within the corresponding comers of the outer bag 52 and, in each case, a plastics

cable tie 62 is passed through the top outer eyelet 60, through the pierced tab 61 and

through the eyelet on the underside of the outer bag 52 before being fastened to itself

to form a securing loop The cable tie 62 is not drawn tight In this way the inner bag

53 is held correctly in position within the outer bag 52 during transit The cable ties 62

can be cut when the inner bag 53 is subsequently to be removed from within the outer

bag 52

The manner in which the bulkhead 14 is fitted within the container 4 prior to

filling of the flexitank will now be described with reference to Figures 12 and 13. As shown diagrammatically m Figure 1 , the container 14 i provided with oppositely facing

channels 70 in its side walls immediately adjacent to the container doors 16 In order

to assemble the bulkhead 14 within the container 4, a lower steel box-section beam 72

is positioned so that its opposite ends are located within the oppositely facing channels

70 in the container side wails Four tubular bars 74 are then inserted into four holes 75

in the upwardly facing surface of the lower beam 72 so that the bars 74 extend vertically

upwardly therefrom, and an upper steel box-section beam 76 is then located so that its

opposite ends are within the channels 70 and so that four holes 77 in the downwardly

facing surface of the upper beam 76 aie located ovei the upper ends of the bars 74 In

order to secure the complete assembly together, two boards 78 and 79 are then bolted

to the upper and lower beams 72 and 76 by means of bolts 80 and wing nuts 81, the

bolts 80 being flat-headed so as not to damage the flexitank which bears against the

boards 78 and 79 from inside the container w hen it is filled with liquid

In a non-illustrated alternative arrangement, the two boards 78 and 79 are

replaced by a flexible sheet and associated harness as the means for securing the upper

and lower beams 72 and 76 and the bars 74 together The sheet is folded over the upper

and lower beams 72 and 76 and its ends are then secured together by buckles provided

on webbing straps secured to the upper and lower parts of the sheet and forming parts

of the harness, so as to form a sleeve which may be tightened over the beams by means

of ratchet elements provided on the straps When the bulkhead and associated flexitank

are to be stored, the beams and bars of the bulkhead may be folded within the flexitank which may then be wrapped within the sheet and its associated harness which then serves

as a carrying case

Such a bulkhead 14 is particularly advantageous since, when disassembled and

stored on an outward or return journey, it occupies only a relatively small space as

compared with conventional wooden bulkheads hich have previously been used in this

application Thus, if a number of flexitanks and their corresponding bulkheads are to be

stored within a single shipping container for return transport for example, the total

number of flexitank and bulkhead sets which can be accommodated w ithin the container

is substantially increased as compared w ith the use of flexitank and bulkhead sets of

conventional construction

Whilst each of the above-described flexitanks comprises a fabric outer bag made

from a woven form polypropylene fibres and subsequently coated with a layer of

polypropylene on at least one side, it should be understood that an outer bag made from

uncoated fabric may be more appropriate in certain applications Furthermore the outer

bag may alternatively be made from other materials, such as nylon polyethylene or

polyester

Claims

CLA IMS

1 A collapsible vessel for the storage and ti ansport of liquids, comprising a

protective outer bag made from stitched woven fabric an inner lining bag made from

flexible Iiquid-impermeable sheet material and contained withm the outer bag, and flow

duct means opening into the inner bag and adapted to pei mit filling of the inner bag with

liquid from outside the outer bag tor storage and transport of the liquid and subsequent

emptying thereof from the mnei bag

2 A vessel according to claim 1 whei em the outer bag is made from stitched

woven polypropylene fabric

3 A vessel according to claim I oi 2, whei em the outer bag is made from fabric

which has been woven from fibres of matei iai coated with a layer of the same material

on at least one side so as to l ender the fabnc substantially Iiquid-impermeable

4 A vessel according to claim 1 , 2 oi 3, wherein the inner bag is made from

polyethylene

5 A vessel according to any preceding claim, wherein the inner bag is secured

within and to the outer bag by means of flanges along opposite edges of the inner bag 6 A vessel according to claim 5, u hei ein the mnei bag is secured within and to the

outer bag by stitching passing thi ough the outer bag and the flanges of the inner bag

7 A vessel according to Claim 1 in which the outer bag is made of nylon

8 A vessel according to any preceding claim in which the outer bag is itself

contained within a generall\ lightweight and low-strength covering which may be one

piece or compπsed of several pieces of polythene to act as a bearing surface between the

outer bag and the inside of a conrainei in order to minimise oi eliminate abrasion of the

outer bag during transport of liquids

9 A vessel according to any preceding claim in which the outer bag is comprised

of two or more layers of woven material with alternating or angularly displaced

directions of weave so as to maximise the strength thereof and minimise the risk of

rupture of the lavers at a single point

10 A vessel according to any one of Claims I to 8 in which the outer bag is made

from a tube of woven material stitched at each end foi closure thereof and optionally

including reinforcement means such as plastics clips or beading along the stitch lines at

each end such that, effectively, rupture of the bag and leakage of liquid could only occur

at such points, thereby minimising the number of possible sites for such to occur 1 1 A vessel according to any one oi Claims 1 to 9 which the outer bag is made

from a tube constructed of a single sheet ot woven material folded in on itself and

stitched lengthwise and at each end

12 A vessel according to any one of Claim I I further incorporating reinforcement

means being provided along the lines of stitching

13 A. vessel according to any preceding claims wheiem the inner and outer bags are

provided with fittings at points around their penphery for detachablv securing the inner

ban within the outer bas.

14 A vessel according to claim 13, wherein the fittings are apertures through which

ties may be passed to secure the inner bag w ithin the outer bag

15 A vessel according to any piecedmg claim wherein the flow duct means

comprises a collar secured to the inner bag at the location of an opening through the wall

of the inner bag and adapted to extend through an opening in the wall of the outer bag

for detachable connection to a connecting pipe

16 A vessel according to any preceding claim w herein a plurality of inner lining

bags made from flexible liquid-impermeable sheet material are contained within the

single outer bag and are provided with respective flow ducts means permitting separate filling of each inner lining bag with liquid and subsequent emptying of the liquid

therefrom

17 A vessel according to any preceding claim, w herein the outer bag is provided

with a harness for detachably securing the

withm a transport container

18 A collapsible vessel substantially as hei einbelore described with reference to

Figures 1 to 1 1 of the accompanying drawings

19 A bulkhead for securing a collapsible vessel within a transport container,

comprising a lower beam having ends which are locatable within oppositely facing

channels in the side walls of the container \ ertical bars having lower ends which are

adapted to be detachably fitted to the lower beam after it has been located within the

channels and upper ends which extend upwai dh of the low er beam, an upper beam

having ends which aie locatable withm the channels in the side walls of the container

after fitting of the vertical bars so as to engage the upper ends of the vertical bars, and

means for securing the upper and lower beams and the vertical bars together

20 A bulkhead according to claim 19, wherein the securing means comprises at least

one sheet of material adapted to overlap the upper and lower beams and to be connected

thereto by bolts 21 A bulkhead foi securing a collapsible vessel within a transport container,

substantially as hereinbefore described with reference to Figures 12 and 13 of the

accompanying drawings