WO2007015842A2

WO2007015842A2 - Flexible container or bladder

Info

Publication number: WO2007015842A2
Application number: PCT/US2006/027793
Authority: WO
Inventors: Benny Chindavong; Tommy Sinakone
Original assignee: Texas Liner Service Llc
Priority date: 2005-07-29
Filing date: 2006-07-18
Publication date: 2007-02-08
Also published as: US20070025649A1; WO2007015842A3

Abstract

A self-supporting bladder for use in transporting or storing foods and liquids is manufactured by folding the ends of a cylindrical section and sealing the open portions of the folded cylinder, resulting in a bladder which supports itself when filled.

Description

TITLE: Flexible Container or Bladder

INVENTOR: Benny Chindavong

Tommy Sinakone

FIELD OF THE INVENTION

The invention concerns the manufacture and use of self-supporting bladders for use in transporting or storing foods and liquids.

BACKGROUND OF THE INVENTION

It has long been desirable to transport foodstuffs, including grains and other solid foodstuffs and liquids such as cooking oils or potable liquids such as water or wine, in cost-

efficient, protective containers. It is also understood that these containers should serve to

protect the foodstuffs against both physical damage and contamination. For example, United

States Patent No. 4,468,812 to Grosvenor discloses a flexible container with a fabric rein- forced rubber body, with an internal lining. The fabric served to reinforce the rubber against

physical damage, and the internal lining served to protect the transported product from

outside influences, such as contamination by contact and reaction with the rubber body, or

bacterial infiltration.

The advent of the widespread use of standardized metal containers for shipping goods

ultimately led to the use of internal container bags, or bladders, so that liquids could be

shipped in such containers, as well as other foodstuffs needing protection from the environ¬

ment. However, the use of flexible internal bladders in shipping containers resulted in

additional engineering difficulties. As disclosed in United States Patent No. 4,054,226 to

Bjelland, et al. , use of such flexible internal bladders resulted in undesirable shifting of cargo

during shipping, and undesirable stresses on the internal bladders during loading and unload- ing of the cargo. Bjelland, et al. discloses one attempt to provide an internal framework to

support such internal bladders, and also discusses other attempted solutions, such as the bulkhead arrangements disclosed in United States Patents Nos. 3,386,605 and 3,696,952.

Although these approaches alleviate some of the concerns involved in using flexible

protective bladders for bulk transportation, each of them requires additional hardware and

space, adding expense and reducing the available volume for the shipped goods. Thus, these approaches add cost and reduce total shipping capacity.

Further, because the bulkhead and other support methods must be used with flexible

bladders in shipment, the bladders themselves must be filled or emptied in position. They

do not have sufficient structural integrity to serve as stand-alone containers, nor do their

structural limitations allow them to be moved in or out of the containers while full, or to be left full at a final destination without additional structural support.

Accordingly, it is an object of the invention to provide a flexible bladder for use in

containerized shipping which does not require additional structural support to maintain the

structural integrity of the bladder while full.

It is another object of the invention to provide a flexible bladder which maximizes

the available shipping volume for liquid or solid foodstuffs carried within containerized

volumes.

It is a further object of the invention to allow such flexible bladders to be deposited

while full at a shipping destination without loss of integrity and without risk of loss or

contamination of the shipped goods. SUMMARY OF THE INVKNTTON

The invention comprises a flexible bladder which is constructed by beginning with

a cylinder of flexible material. The cylinder may be formed by rolling an essentially rectangular section of flexible material into a cylindrical shape, and joining the ends to form a

cylinder. In the preferred embodiment of the invention, the flexible material used is food

grade PVC, such as linear low density polyethylene made by GSE Lining Technology, Inc.,

of Houston, Texas, with a coating to make it acceptable under FDA standards for transport¬

ing foodstuffs in direct contact.

Further, if a cylinder is formed by rolling an essentially rectangular piece of material

into a cylinder, it is preferred to join the ends of the material together by welding, such as by

a wedge- weld. Those of skill in the art will recognize that other types of welds may be used, or other types of joins could be used, so long as the final join is tight, sufficiently strong for

the purpose, and does not introduce a risk of contamination to the transported goods.

Formed in this way, the cylinder will have opposing, essentially circular openings at

a first end and second end. As used herein, the longitudinal axis of the cylinder is that axis

parallel to a line drawn between the first open end and the second open end of the cylinder,

and the radial axis is the axis perpendicular to the longitudinal axis.

The invention may be embodied in one of two orientations. In the first orientation,

the radial axis of the cylinder will form the long dimension of the final form, which is

preferably an essentially rectangular parallelipiped, sized to fit the interior space of a con¬

tainer vessel for shipping, or, if to be used solely as a stand-alone container, sized to the desired dimensions. In the second orientation, the longitudinal axis of the cylinder will form

the long dimension of the final form, which is preferably an essentially rectangular parallel-

ipiped, sized to fit the interior space of a container vessel for shipping, or, if to be used solely

as a stand-alone container, sized to the desired dimensions. Those of skill in the art will understand that the radius of the cylinder and its length along its longitudinal axis will be

selected based on the desired orientation and the desired dimensions of the final form of the

bladder.

In either orientation, the construction of the bladder requires that the first open end and the second open end of the cylinder are folded to create a pair of opposed shaped openings, which can be closed with a shaped seal which are shaped to the formed shapes of

the opening, and fixed in place by a sealing means, such as a weld, hi the preferred embodi¬

ment, rod welds are used to seal the shaped seals into the ends of the cylinder.

It will be recognized by those of skill in the art that the original cylinder will be formed by this process into a shape which is not cylindrical, but is preferably a portion of a

rectangular parallelipiped. However, throughout this description, the word "cylinder" is used

to refer to that portion of the structure which begins as a cylinder and is manipulated into other shapes and ultimately forms a portion of the body of the flexible bladder. This label

is used not as a limitation to the form of the originally cylindrical body, but rather as a

convenient label for a body which is at one point in cylindrical form but must be manipulated

into other forms for the creation of the final flexible bladder. In the first orientation, the cylinder is folded by pressing inward and down from

diametrically opposed points at the first open end of the cylinder, forming an essentially flat

body comprised of four trapezoidally-shaped segments. The four trapezoidally-shaped

segments comprise two pairs of segments, with each pair having its major bases essentially

parallel and separated by an essentially rectangular gap, and its minor bases forming two of the sides of an irregular octagon. The bases of the first pair of trapezoidally-shaped segments

are essentially orthogonal to those of the second pair.

Folded in this way, the first open end of the cylinder is formed into an essentially rectangular open segment, bordered by the first pair of trapezoidally-shaped segments. It is

preferable to trim these two trapezoidally-shaped segments (the two on the top of the folded

cylinder, if it is laid flat on a surface) to remove triangular segments at the four ends of the

two major bases of the trapezoidally-shaped segments. Removing this material makes it easier to fold the outer edges of the underlying, essentially orthogonal second pair of

trapezoidally-shaped segments upward and inward, and removes excess material which

would preclude such a fold from laying flat once made.

A rectangular seal, shaped to match the form of the rectangular open segment bor¬

dered by the first pair of trapezoidally-shaped segments and sized to allow sufficient overlap

with those segment to provide a sufficient seal against pressure from inside, once the bladder

is completed. Preferably, the long edges of the rectangular seal are place under the long

bases of the first pair of trapezoidally-shaped segments, so that the edges of the rectangular

seal will be on the "inside" of the bladder. In this way, internal pressures will act to press the seal more tightly against the remainder of the bladder. The rectangular seal is preferably sized so that the length of its long axis is less than the distance between the short bases of the second pair of trapezoidally shaped segments, and preferably shortened from this distance

by essentially the total length of the trimmed triangular-shaped segments previously cut from

the first pair of trapezoidally-shaped segments. If, as is preferred, these triangular-shaped

segments have been trimmed from the first pair of trapezoidally-shaped segments, an

appropriately sized rectangular seal can simply be slid into position. Now the outer edges

of the underlying, essentially orthogonal second pair of trapezoidally-shaped segments are

folded upward and inward, covering the ends of the rectangular seal. At this juncture the seal

can be sealed to the folded cylinder, preferably by the steps of heat sealing, buffing, and rod welding (or extrusion welding) the edges of the rectangular shaped opening in the folded

cylinder to the rectangular seal, similarly sealing the folded-over flaps from the underlying, essentially orthogonal second pair of trapezoidally-shaped segments, and sealing the short

diagonal segments between the folded-over flaps and the first pair of trapezoidally shaped

segments.

Those of skill in the art will recognize that it is possible to turn the folded cylinder

over, exposing the remaining rectangular shaped opening, and to repeat the trimming and

sealing process detailed above to insert a second rectangular seal. However, the two original rectangular openings were essentially orthogonal to each other, and the resulting shape of the

bladder would approximate that of a twisted ball with flat ends. While such a shape is possibly useful and not beyond the scope of this invention, it is not the preferred result of an

essentially rectangular parallelipiped.

Accordingly, in the preferred embodiment, the folded cylinder is turned over and unfolded. Due to the presence of the rectangular seal and the effects of the prior folds, the

unfolded cylinder will have a shape approximate to that of an open box. The sides of this

structure are now refolded, to form the second open end of the cylinder into a shape with an

essentially rectangular opening which parallels the shape of the first shaped seal. This

folding is accomplished by trimming four essentially triangular-shaped segments from the

edge of the second open end of the cylinder at the corners that are formed by pressing the wall of the cylinder into essentially the rectangular shape of the first shaped seal. The wall

of the cylinder is then folded inward at approximately its midpoint parallel the long axis of the first shaped seal, forming the cylinder into a folded rectangle with essentially trapezoidally-shaped ends. This folding creates an essentially rectangular shaped opening

at the second open end of the cylinder, which can be sealed by an appropriately sized,

rectangular second shaped seal in effectively the same manner as the first shaped seal.

Those of skill in the art will recognize that the bladder must be equipped with a vent

and at least one inlet-outlet valve, to allow the bladder to be used for transporting foodstuffs.

Because the first and second shaped seals in this first orientation form the intended top and

bottom of the bladder, a vent, is preferably centered in the first or second shaped seal, which

will then become the top of the bladder for operational purposes. Similarly, a ball valve,

such as model number VSF204FP, manufactured by Banjo Corporation, can be used as an inlet-outlet valve. Those of skill in the art will recognize that an inlet-outlet valve may be

positioned on the top of the bladder, or along the lower edge of one of the sides. Precise

positioning of the vent and the inlet-outlet valve is a matter of preference and utility, and

does not affect the scope of this invention. However, the vent and inlet-outlet valve must be

appropriately positioned at least before the second shaped seal is sealed to the cylinder.

Constructed as detailed above, the bladder thus formed will, when filled through the

inlet-outlet valve, assume the shape of a rectangular parallelipiped, with sufficient structural

integrity that no other framework is necessary to support it. As those skilled in the art will recognize, if it is appropriately sized it may be placed inside a shipping container and will

thus allow maximum use of the space in such a container for transporting goods, will

simultaneously protecting the goods from loss or contamination.

In the second orientation, the cylinder is folded by first pressing it flat along its

longitudinal axis, then folding a section of cylinder near the first open end to so that the first

open end forms an essentially rectangular opening bordered by two essentially equilateral

triangles, oriented so that the bases of the two triangles form the sides of the essentially

rectangular opening. Similarly to the procedure described above, it is preferable to trim

triangular shaped segments from the four ends of the bases of the two essentially equilateral

triangles, to create a slot so that the first shaped seal may be more easily slid into position,

and to facilitate the folding over of the edges at the flat ends of the essentially rectangular

opening. A first shaped seal may then be slid into position. As before, it is preferable to position the first shaped seal so that its edges will be inside the bladder relative to the edges of the first open end of the cylinder, so that internal pressures will serve to enhance the seal.

Similar to the procedure described above regarding the first orientation, the flat edges

of the first open end of the cylinder are folded over flat against the first shaped seal, and the

first shaped seal is preferably welded in place. Repeating this procedure at the second open

end of the cylinder with a second shaped seal results in a bladder which, when filled, will form a rectangular parallelipiped with the first and second shaped seals forming the ends,

rather than the top and bottom, of the bladder. As discussed above, those of skill in the art

will recognize that it is necessary to appropriately position and install a vent and an inlet-

outlet valve during construction of the bladder.

Those of skill in the art will also recognize that different seal shapes may be used with modified folding techniques, to form different variations on the final shape of the bladder. For example, octagonal seals could be used to create an octagonally-shaped bladder,

or triangular seals could be used to form triangular bladders, or other shapes could be used. These variations can be made without departing from the spirit of the invention. However,

constraints of conventional shipping methods and structural integrity do not make such

variations preferable.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. IA is a side view of the beginning materials of a first embodiment of the inven¬

tion. Fig. IB is a oblique view of a cylindrical piece used in constructing a first embodi¬

ment of the invention.

Fig. 1C is an oblique view of the cylindrical piece of Fig. IB during the construction

process of a first embodiment of the invention.

Fig.2 A is an oblique view of the cylindrical piece of Fig. IB during the construction

process of a first embodiment of the invention.

Fig. 2B is an oblique view of the cylindrical piece of Fig. IB during the construction

process of a first embodiment of the invention.

Fig. 2C is an oblique view of the cylindrical piece of Fig. IB during the construction

process of a first embodiment of the invention.

Fig. 2D is an oblique view of a first embodiment of the invention in a partially constructed state.

Fig. 3A is an oblique view of a first embodiment during the construction process'

continuation from Fig. 2D.

Fig. 3B is an oblique view of a first embodiment during the construction process¹

continuation from Fig. 3A.

Fig. 3C is an oblique view of the final assembly of a first embodiment.

Fig. 4A is a face view of the beginning materials of a second embodiment of the

invention..

Fig. 4B is a oblique view of a cylindrical piece used in constructing a second embodi¬

ment of the invention. Fig. 4C is an oblique view of the cylindrical piece of Fig. 4B during the construction

process of a second embodiment of the invention..

Fig. 4D is an oblique view of the view of Fig. 4C proceeding further in the construc¬

tion process of a second embodiment of the invention.

Fig. 5 A is an oblique view of the view of Fig. 4D proceeding further in the construc¬

tion process of a second embodiment of the invention.

Fig. 5B is an oblique view of the view of Fig. 5 A proceeding further in the construc¬

tion process of a second embodiment of the invention.

Fig. 5C is an oblique view of the view of Fig. 5B proceeding further in the construc-

tion process of a second embodiment of the invention.

Fig. 5D is an oblique view of the view of Fig. 5C proceeding further in the construc¬

tion process of a second embodiment of the invention.

Fig. 5E is an oblique view of the final assembly of a second embodiment.

DETAILED DESCRIPTION

Referring to Fig. 1, the beginning of construction of a first orientation of a bladder

of the present invention is shown. An essentially rectangular strip of material 110, such as

food-grade PVC₃ is rolled into a cylindrical shape and formed into a cylinder 114 by wedge-

weld 112. Cylinder 114 has a first open end 115 and a second open end 117. Cylinder 114

is then folded at first open end 115 by pressing inward at diametrically opposed positions

116, 118 and folds 120 are formed in the cylinder 114. Referring to Fig.2, further steps in the construction of the first orientation are shown.

Folds 220 in cylinder 214 are completed, so that cylinder 214 lays essentially flat. The

folding of cylinder 214 has formed a first pair of essentially trapezoidally shaped segments

222 and a second pair of essentially trapezoidally shaped segments 224. Each pair of

essentially trapezoidally shaped segments defines an essentially rectangular shaped opening;

the first pair of essentially trapezoidally shaped segments 222 defines essentially rectangular

shaped opening 226, and the second pair of essentially trapezoidally shaped segments 224

defines essentially rectangular shaped opening 228.

It is preferable to trim essentially triangular shaped segments (not shown) from the

ends 230, 232 of the first pair of essentially trapezoidally shaped segments 222. Such

trimming facilitates the folding of the ends 234, 236 of the second pair of essentially trape¬

zoidally shaped segments 224, and allows first shaped seal 238 to be easily slid into position

under the edges of the first pair of essentially trapezoidally shaped segments 222, as depicted

by the directional arrow in Fig. 2B..

With the first shaped seal 238 in position, the ends 234, 236, of the second pair of

essentially trapezoidaliy shaped segments 224 are folded over the first shaped seal 238, as

depicted by the directional arrow in Fig. 2C. Rod welds 242 are made to sealably connect

first shaped seal 238 to the first pair of trapezoidally shaped segments 222, and to seal joins

240 between the ends 234, 236, of the second pair of essentially trapezoidally shaped

segments 224 and the first pair of essentially trapezoidally shaped segments 222. Cylinder 214 can then be turned over and unfolded as shown in Fig. 2D. The

presence of first shaped seal 238 causes cylinder 214 to form the shape of a rectangular

parallelipiped 244, with the open top being the second open end 217 of cylinder 214.

Triangular segments 248, 250 (indicated by dashed lines) are trimmed from the "corners" of

cylinder 214 to facilitate the folding of second open end 217 of cylinder 214.

Referring now to Fig. 2D and Fig. 3, cylinder 314 (214 of Fig. 2) is folded again

along fold lines 246 of Fig. 2D, allowing cylinder 314 to lay in a folded flat shape and

folding second open end 317 of cylinder 314 to form an essentially rectangular opening.

Second shaped seal 338 may then be slid into position, as depicted by the directional arrow

of Fig. 3 A. Second shaped seal 338 comprises vent hole 324 for positioning of a vent (not

shown) and valve hole 326 for positioning of an inlet-outlet valve (not shown). As discussed

previously, the positioning of vents and valves is a matter of engineering preference and needs of the particular application, and these hole positions are shown by way of example

only.

Second shaped seal 338 is positioned so that it lays under essentially trapezoidal end

segments 316 and 318, and flaps 320 and 322 are folded over the sides of second shaped seal

338. As with the first shaped seal (238 of Fig. 2), rod welds 328 seal the sides of the second

shaped seal 338 to the cylinder 314, and also seal joins at the corners.

As shown in Fig. 3C, when the bladder 330 is filled, it now forms an essentially

rectangular parallelipiped. Referring to Fig. 4, the beginning steps to manufacture a second orientation of the

invention are shown. A sheet 410 of material such as food-grade PVC is rolled into a

cylinder 414 with a first open end 416 and a second open end 418, and fixed in that shape

with wedge welds 412. Those skilled in the art will recognize that the circumference of

cylinder 414 is limited by the size of sheet 410, and that, if necessary to achieve the desired

size for the final bladder, multiple sheets of material can be joined together, as by wedge-

welding, to form a sufficiently large sheet. Cylinder 414 is then flattened along its longitudi¬

nal axis, as depicted by the directional arrows in Fig. 4C. A section 420 of cylinder 414 is

folded near first open end 416, as depicted by the directional arrow of Fig. 4D.

Referring to Fig. 5, the first open end 516 of cylinder 514 is opened and one-half of

the material 524 is folded back (as shown by the directional arrow of Fig.5A) along fold line

A-A', while the sides are folded inward to form essentially triangular segments 526, which

define a rectangular slot 528.

Triangular sections (not shown) are preferably trimmed off of the corners 530, 532

of the essentially triangular sections 526, allowing room to easily slide first shaped seal 534

into position as depicted by the directional arrow of Fig. 5B. With first shaped seal 534 in

position in the first open end 516 of cylinder 514, edges 536 and 536 are folded over first

shaped seal 534 as depicted by the directional arrows of Fig. 5C. Rod welds 540 are prefera¬

bly used to seal the first shaped seal 534 into the first open end 516 of cylinder 514, and to

seal the joins between the essentially triangular sections 526 and edges 536 and 538. Installation of the second shaped seal (not shown) involves repeating the steps

depicted in Figs. 4D, 5A, 5B, 5C, and 5D and described above at the second open end (418

of Fig. 4B) of the cylinder 514. As shown in Fig. 5E, when filled the cylinder 514 will be

formed into an essentially rectangular parallelipiped.

As with the first orientation, a vent hole 542 and inlet-outlet valve hole 544 (or 546

if a lower-end position is used for the inlet-outlet valve) should be provided, and the appro¬

priate internal hardware installed before the cylinder 514 is completely sealed.

The above examples are included for demonstration purposes only and not as limita¬

tions on the scope of the invention. Other variations in the construction of the invention may

be made without departing from the spirit of the invention, and those of skill in the art will recognize that these descriptions are provide by way of example only.

Claims

I claim:

L A method of forming a container from a flexible material, comprising

forming a cylinder from a flexible material so that said cylinder has a first open end and a second open end,

folding said first open end of said cylinder to create a first shaped opening,

sealing said first shaped opening with a first shaped seal, folding said second open end of said cylinder to create a second shaped

opening, and

sealing said second shaped opening with a second shaped seal.

2. The method of claim 1 , wherein the step of folding said first open end of said

cylinder to create a first shaped opening includes the step of forming said first shaped

opening to a rectangular shape.

3. The method of claim 1 , wherein the step of folding said second open end of

said cylinder to create a second shaped opening includes the step of forming said second

shaped opening to a rectangular shape.

4. The method of claim 1, wherein the step of folding the first open end of said

opening to a first rectangular shape and the step of folding said second open end of said

cylinder to create a second shaped opening includes the step of forming said second shaped opening to a second rectangular shape.

5. The method of claim 4, additionally comprising the step of forming said first

rectangular shape and said second rectangular shape so that one dimension of each of said rectangular shapes is longer than the perpendicular dimension of that shape.

6. The method of claim 4, additionally comprising the step of orienting said first

rectangular shape and said second rectangular shape to be substantially parallel.

7. The method of claim 5, additionally comprising the step of orienting said first

rectangular shape and said second rectangular shape so that the longer dimension of said first

rectangular shape is substantially parallel to the longer dimension of said second rectangular shape.

8. The method of claim 1, wherein said step of sealing said first shaped opening

with a first shaped seal additionally comprises the step of welding said first shaped seal to

said cylinder.

9. The method of claim 1, wherein said step of sealing said second shaped

opening with a second shaped seal additionally comprises the step of welding said second shaped seal to said cylinder.

10. A container formed of flexible material comprising

a cylindrical body,

a first shaped seal, wherein said first shaped seal is sealably joined to a first folded end of said cylindrical body, and a second shaped seal, wherein said first shaped seal is sealably joined to a

second folded end of said cylindrical body.

11. The container of claim 10, wherein said first shaped seal is rectangular.

12. The container of claim 10, wherein said second shaped seal is rectangular.

13. The container of claim 10, wherein said first shaped seal is square.

14. The container of claim 10, wherein said second shaped seal is square.

15. The container of claim 10, wherein said first shaped seal is welded to said first folded end of said cylindrical body.

16. The container of claim 10, wherein said second shaped seal is welded to said first folded end of said cylindrical body.