DESC:FIELD OF THE INVENTION
[001] The present disclosure generally relates to flexible tanks used in containers to transport non-hazardous liquid, and more specifically, relates to a reinforced flexible tank that prevents containers from bulging due to the pressure exerted by the liquid.
BACKGROUND OF THE INVENTION
[002] Flexible tank also known as flexitank is used in containers to transport non-hazardous liquid from one location to another. While transporting liquid, the trucks or lorries that carry these containers are bound to pass through patchy roads and rough terrains that causes the liquid to slosh or surge. Sloshing or surging of the liquid is the to and fro motion of the liquid within the container and can occur because of the rough roads, or sharp acceleration or deceleration of the truck. Sloshing or surging by the liquid exerts pressure on the walls of the container and can damage the walls of the container. They may result in deformation and bulging of the container making it unsuitable for further transportation.
[003] It is known that containers use bulkheads/accessories and horizontal load bars to prevent damages to the container wall. However, having bulkheads and load bars are inconvenient for transferring the liquid to and from the container. It is also known that containers use vertical bars along the container walls, to protect damage to the wall due to the pressure exerted by the liquid. Typically, the walls of the container are reinforced by placing 2” x 2” (50 x 50mm) Square, 2.0/2.2 mm thick heavy-duty box section tubes or vertical bars. The position or spacing of these vertical runners or vertical bars is crucial and depending on the severity of the containers condition the quantity of runners required is determined. Usually, the containers will have two or three runners on each side of the container and these runners absorb all the lateral forces imparted by the sloshing liquid and do not pass that on to the container walls, thereby protecting them from bulging. However, there is no fixed standard on how many runners are required to reinforce a container for higher payloads.
[001] According to the International Organization for Standardization (ISO)/Institute of International Container Lessors (IICL) recommendations, the deformation limit for sidewall panels is a maximum of 10 mm beyond the plane of the side surfaces of the corner casting fittings of the container. This limit has been exceeded in many incidents, where the pressure placed on the sidewall panels has resulted in them bulging beyond accepted ISO external dimensions and tolerances, leading to permanent deformation. Hence, many industry cargo operators have imposed limits on the quantity of liquid that may be carried in a flexitank.
[002] It is desired to have a flexitank that can accommodate high pay loads, at the same time withstand pressure arising due to sloshing of the liquid during transportation and further prevent bulging of the container wall.
BRIEF DESCRIPTION OF THE FIGURES
[003] These and other features, aspects, and advantages of the exemplary embodiments can be better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
[004] FIG. 1A, 1B, 1C and 1D illustrates various views of the reinforcement structure within an antibulging flexitank in accordance with an embodiment of the present disclosure;

[005] FIG. 2A and FIG. 2B illustrates guidance marks on the flexitank in accordance with an embodiment of the present disclosure;

[006] FIG. 3A and 3B illustrates external fittings of the flexitank in accordance with an embodiment of the present disclosure;

[007] FIG. 4 illustrates sine waves representing stress level when a conventional flexitank and an antibulging reinforced flexitank is loaded, in accordance with one embodiment of the present disclosure;

[008] FIG. 5 illustrates sine waves representing deformation of the back wall of a conventional flexitank and an antibulging reinforced flexitank when loaded, in accordance with one embodiment of the present disclosure;

[009] FIG. 6 illustrates sine waves representing deformation of the right side wall of a conventional flexitank and an antibulging reinforced flexitank when loaded, in accordance with one embodiment of the present disclosure; and

[0010] FIG. 7 illustrates sine waves representing deformation of the left side wall of a conventional flexitank and an antibulging reinforced flexitank when loaded, in accordance with one embodiment of the present disclosure.

[0011] Further, skilled artisans will appreciate that elements in the figures are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the figures by conventional symbols, and the figures may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the figures with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

DETAILED DESCRIPTION OF THE INVENTION
[0012] For promoting an understanding, the principles of the invention, reference will now be made to the embodiments illustrated in the figures and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

[0013] It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be restrictive thereof.

[0014] The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion such that a process or method that comprises a list of steps does not comprise only those steps but may comprise other steps not expressly listed or inherent to such a process or a method. Similarly, one or more devices or sub-systems or elements or structures or components proceeded by "comprises... a" does not, without more constraints, preclude the existence of other devices or other sub-systems or other elements or other structures or other components or additional devices or additional sub-systems or additional elements or additional structures or additional components. Appearances of the phrase “in an embodiment”, “in another embodiment” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

[0015] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The system, methods, and examples provided herein are illustrative only and not intended to be limiting.

[0016] In addition to the illustrative aspects, exemplary embodiments, and features described above, further aspects, exemplary embodiments of the present disclosure will become apparent by reference to the drawings and the following detailed description.

[0017] A flexitank, is a bladder, designed to fit inside a 20ft general freight container, thereby converting the freight container into a non-hazardous bulk liquid transportation unit as defined by the International Maritime Organization (IMO), the International Labour Organization (ILO) and the United Nations Economic Commission for Europe (UNECE) code of practice for packing of cargo transport units (CTU Code Reference-57). The flexitank is used for transport and or storage of a non-regulated liquid inside a CTU.

[0018] Typically, a 20 ft freight container having flexitank should generally be rated to a minimum 30,480 kg, irrespective of the size of the flexitank. The actual sidewall strength is a function of a container’s permitted payload, ie 0.6 × payload (according to ISO 1496-1 Series 1 freight containers – specification and testing). Therefore, the sidewall panels of a 30 mt container will have been tested to a greater load bearing capability than, say, a 24 mt container. The sidewall test requires a general freight container to be subjected to an internal loading uniformly distributed and arranged to allow free deflection of the sidewall and its longitudinal members. The ISO Standard requires that, upon completion of the test, the container exhibits neither permanent deformation that will render it unsuitable for use, nor any abnormality that will render it unsuitable for use, and that the dimensional requirements governing handling, securing and interchange are satisfied. Therefore, for a 30 mt container, the test load will be of the order of 16.8 mt. However, since a flexitank does not place a uniform loading over the full area of a sidewall, a gross liquid cargo weight of 24,000 kg is the recommended maximum by some flexitank operators, while some container operators maintain that there should be a lower limit for the liquid cargo weight. The problems faced by the customer today is bulging of the container walls after the flexitank is loaded. Once the bulging occurs, the customer is forced to cross stuff the product into another container. The customer faces losses in different fronts. The total loss includes (1) Container replacement, (2) New Flexitank in new container, (3) Cross stuffing expenses, (4) Transportation & (5) Loss of cargo, if any. The present disclosure solves these problems.

[0019] Embodiments of the present disclosure describes a reinforced antibulging flexitank for transportation of liquid in containers from one location to another.

[0020] FIG. 1A, 1B, 1C and 1D illustrates various views of the reinforcement structure within the flexitank in accordance with an embodiment of the present disclosure. The reinforcement structure, which is a tube of width slightly lower than the flexitank liner, is wrapped around the flexitank in the designated place. These tubes that resemble ribs help in breaking the wave formed inside the anti-bulging flexitank 100 due to the sloshing of the liquid. These tubes (Ribs) are further reinforced with a webbing 105. Webbing is inserted in the middle as the wave breaker. These additions break the wave generated by the liquid inside the tank to such an extent that its crest is significantly lower so that the center of gravity of the load is below the halfway point. In some embodiments, the tube and webbings can be replaced by a belt or a strap or any other similar structure that can provide reinforcement to the flexitank. In one embodiment, the number of ribs can be two, however one should note that the number of ribs can be increased or decreased based on the reinforcement required for the flexitank/container combination.

[0021] FIG. 1B illustrates the liner with ribs whose width is slightly lower than the liner. In one embodiment, the liner with ribs is placed anywhere between 230 cm to 400 cm.

[0022] FIG. 1C illustrates the ribs when the flexitank is being inflated. As shown in FIG. 1C, these tubes (ribs) are further reinforced with a webbing 105 running right in the middle. The ribs are strengthened with the webbing and does not stretch as much as the body of the flexitank. The body of the flexitank, by being constructed with a film tends to take the shape of the liquid inside, but the rib does not entirely take that shape, thereby breaking the wave.

[0023] Referring to FIG. 1D now, FIG. 1D depicts the dimensions of the ribs in accordance with one embodiment of the present disclosure. The rib reinforcement structure is constructed from a tubular woven Polypropylene (PP) fabric. This fabric is further reinforced with a webbing ( 2.0mtr capacity/strength) running right in the middle. This webbing is the skeleton of the reinforcement structure. In one embodiment, the Ribs dimension in Length/Diameter = 3950mm x Width = 450mm with the skeleton running through the middle being 5cms in width. The reinforcement structure is wrapped around the inner part (Liner) of the flexitank. For it to remain in the designated place it is pasted with a gum tape to the liner. It is to be noted that the flexitank can include one or more rib reinforcement structure.

[0024] It should be noted that the position of the ribs or tubes and dimensions, the webbing dimensions, the liner dimensions and stitching patten may vary and will be placed accordingly in the anti-bulging flexitank for breaking the waves of the liquid and absorb the pressure and prevent bulging of the container. The antibulging flexitank is a single compartment flexitank, also called as a single unit flexitank with inbuilt reinforcement ribs or tubes with webbings. A single compartment flexitank with the inbuilt reinforcement ribs with webbings can prevent sloshing of the liquid and prevent bulging of the container.

[0025] FIG. 2A and FIG. 2B illustrates guidance marks on the flexitank in accordance to an embodiment of the present disclosure. The guidance marks depicted by arrows are printed on four sides of the fabric. The arrow marks indicate the exact position for the webbing belt with carabina to be installed. There are 4 clear signs (markers 205) as depicted in FIG. 2B, printed on the flexitank to assist the operator in installation.

[0026] FIG. 3A and 3B illustrates external fittings 305 of the flexitank in accordance with an embodiment of the present disclosure. These external fittings 305 are constructed from webbing and carabina, with carabina being fitted to either end of the flexitank. These external fittings 305 provide additional reinforcement and protect the ribs. Further, these external fittings are made with webbing with a carabina attached at either end.

[0027] The carabina is installed in an X shaped arrangement as depicted in FIG. 3B. The X shaped arrangement of the carabina provides further reinforcement to the flexitank.

[0028] FIG. 4 is a graphical representation of stress level when a conventional flexitank and an antibulging reinforced flexitank is loaded, in accordance with one embodiment of the present disclosure.

[0029] In FIG. 4, 405 represents a sine wave indicating stress level when a conventional (normal) flexitank, i.e. a flexitank without inbuilt reinforcement ribs or tubes with webbings, is loaded with liquid. 410 represents a sine wave indicating stress level when a flexitank with inbuilt reinforcement ribs or tubes with webbings, is loaded with liquid.

[0030] Here the X-axis represents the time and Y-axis represents the amplitude of the wave created. As seen in FIG. 4, the amplitude of the wave 405 is significantly higher in comparison to the amplitude of the wave 410. This is because the inbuilt reinforcement ribs act as shock/stress absorber, thereby reducing the amplitude of the wave thus reducing the force on the walls of the container.

[0031] In one example, a load impact test was conducted to evaluate the performance of a disposable bulk packaging system for shipment of non-hazardous liquid in 20’ containers. The study included two flexitanks of similar size. Both the flexitanks had a maximum capacity of 24,000 liters and consisted of four layers of low-density polyethylene plus an outer layer of woven polypropylene.

[0032] The Test Equipment preparation.
[0033] In one example, it was decided to pick a Random 20’ Container. The container was rated heavy duty and mounted on a 20’ trailer. The container was divided into three segments-one each for the side walls and one for the nose end. Each wall was further divided into 2 subsegments- 1/3rd from the bottom & 2/3rd from the bottom. A string was run on each subsegment (1 & 2) so that the distance from the string to the container wall could be measured using a Vernier Caliper. The 2nd ,4th,5th & 7th trough of the container corrugation were identified on subsegment 1 & 2 for taking the measurements. Similarly for the side walls, markers on subsegment 1 & 2 were identified on the 3rd,6th,9th,12th ,15th & 18th trough. The equipment was now ready with marker points.

[0034] The Test
[0035] A normal flexitank -Bottom Load Bottom Discharge flexitank was installed in the container & the measurement of the distance from the string to the wall were noted down. Ground water was used to fill the flexitank.24,000 Liters of water was pumped into the tank. The quantity of water was ascertained using a flow meter. The container was moved by road from a first location to a second location which was a distance of 280 Kms. This route was chosen for its winding and hilly topography. At destination the measurements were taken down. Further, the water from the flexitank was completely drained & third set of measurements were noted down.

[0036] TEST VALUES FOR END WALL-NORMAL TANK
[0037] Table-1
SL NO BEFORE FILLING (X) BEFORE DISCARGE (Y) AFTER DISCHARGE (Z) A(Y-X) B(X-Z) AVG A AVG B
1(2) 102 95 100 7 2 9 4.88
1 (4) 101 90 96 11 5
1 (5) 100 87 94 13 6
1 (7) 103 94 98 9 5
2 (2) 102 94 98 8 4
2(4) 99 92 93 7 6
2(5) 99 90 94 9 5
2(7) 106 98 100 8 6

[0038] TEST VALUES FOR END WALL-ANTI BULGING TANK
[0039] Table-2
SL NO BEFORE FILLING
(X) BEFORE DISCARGE
(Y) AFTER DISCHARGE
(Z) A
(Y-X) B
(X-Z) AVG A AVG B
1(2) 96.8 92 105 4.8 -8.2 5.875 -3.19
1 (4) 93.7 88 100 5.7 -6.3
1 (5) 96.8 91 102 5.8 -5.2
1 (7) 104.1 98 107 6.1 -2.9
2 (2) 102.2 96 104 6.2 -1.8
2(4) 98.8 92 99 6.8 -0.2
2(5) 98.9 93 99 5.9 -0.1
2(7) 105.2 99.5 106 5.7 -0.8

[0040] TEST VALUES FOR RT SIDE WALL-NORMAL TANK
[0041] Table-3

SL NO BEFORE FILLING
(X) BEFORE DISCARGE
(Y) AFTER DISCHARGE
(Z) A
(Y-X) B
(X-Z) AVG A AVG B
1(3) 99 88 99 11 0 15.33 0.5
1(6) 100 81 97 19 3
1(9) 94 76 93 18 1
1(12) 98 80 94 18 4
1(15) 98 84 100 14 -2
1(18) 116 106 118 10 -2
2(3) 94 81 95 13 -1
2(6) 94 76 93 18 1
2(9) 92 75 93 17 -1
2(12) 92 75 92 17 0
2(15) 92 76 90 16 2
2(18) 108 95 107 13 1

[0042] TEST VALUES FOR RT SIDE WALL -ANTI BULGING TANK
[0043] Table-4
SL NO BEFORE FILLING
(X) BEFORE DISCARGE
(Y) AFTER DISCHARGE
(Z) A(Y-X) B(X-Z) AVG A AVG B
1(3) 96.8 85 95 11.8 1.8 11.53 0.483333333
1(6) 95.7 81 97 14.7 -1.3
1(9) 91.6 80 91 11.6 0.6
1(12) 89.5 79 88 10.5 1.5
1(15) 94 81 93 13 1
1(18) 101.4 90.4 100 11 1.4
2(3) 98.8 81 99 17.8 -0.2
2(6) 97.8 81 98 16.8 -0.2
2(9) 90.5 80 91 10.5 -0.5
2(12) 88.5 81.8 87 6.7 1.5
2(15) 91.5 85 89 6.5 2.5
2(18) 94.7 87.3 97 7.4 -2.3

[0044] TEST VALUES FOR LEFT SIDE WALL – NORMAL TANK
[0045] Table-5
SL NO BEFORE FILLING X BEFORE DISCARGE Y AFTER DISCHARGE Z A(Y-X) B(X-Z) AVG A (MAX LIMIT IS 40 MM) AVG B (MAX LIMIT IS 7 MM FOR SIDE WALLS AND 5 MM FOR END WALL
1(3) 110 88 105 22 5 25.17 4.33
1(6) 101 75 95 26 6
1(9) 98 71 94 27 4
1(12) 97 73 95 24 2
1(15) 119 94 115 25 4
1(18) 101 84 98 17 3
2(3) 107 81 100 26 7
2(6) 94 64 86 30 8
2(9) 95 66 92 29 3
2(12) 97 68 94 29 3
2(15) 111 83 107 28 4
2(18) 102 83 99 19 3

[0046] TEST VALUES FOR LEFT SIDE WALL – ANTIBULGING TANK
[0047] Table-6
SL NO BEFORE FILLING X BEFORE DISCARGE Y AFTER DISCHARGE Z A(Y-X) B(X-Z) AVG A (MAX LIMIT IS 40 MM) AVG B (MAX LIMIT IS 7 MM FOR SIDE WALLS AND 5 MM FOR END WALL
1(3) 100 89 100 11 0 14.93 1.50
1(6) 99.9 72 100 27.9 -0.1
1(9) 97.8 82 95 15.8 2.8
1(12) 96.7 81.8 94 14.9 2.7
1(15) 103.1 87 102 16.1 1.1
1(18) 106.1 89.6 106 16.5 0.1
2(3) 99.8 90.2 99 9.6 0.8
2(6) 99.9 90.7 97 9.2 2.9
2(9) 94.7 87.8 92 6.9 2.7
2(12) 92.6 86.8 91 5.8 1.6
2(15) 111.4 90.1 108 21.3 3.4
2(18) 115 90.8 115 24.2 0

[0048] INFERENCE FROM TEST RESULTS
[0049] The readings from the table indicate that in all three segments (Back Wall, Left Side Wall & the Right Side Wall), the deformation in a normal Flexitank is higher. The deformation for the back wall of the wall opposite to door side is illustrated in FIG. 5. The deformation for the right side wall when facing door side is illustrated in FIG. 6. The deformation for the left side wall when facing door side is illustrated in FIG. 7.

[0050] Further, it is observed that the deformation in left side wall of a normal flexitank was considerably higher. There was a significant vertical component to the vector. It can be inferred from the test that the stress exerted by the sloshing liquid is significantly greater in a normal flexitank when compared to the Antibulging Flexitank. The Anti Bulging feature (reinforcement with ribs) of the Anti-Bulging Flexitank did mitigate the effects of the sloshing by reducing the amplitude within the flexitank, thereby reducing its impact on the walls.

[0051] In summary, the antibulging flexitank for transporting liquid includes a rib reinforcement structure wrapped around the flexitank, wherein the rib reinforcement structure comprises webbing for reinforcement. The rib reinforcement structure breaks the wave formed inside antibulging tank due to sloshing of the liquid. The flexitank may have one or more rib reinforcement structure.

[0052] While specific language has been used to describe the disclosure, any limitations arising on account of the same are not intended. As would be apparent to a person skilled in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein.

[0053] The figures and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, orders of processes described herein may be changed and are not limited to the manner described herein. Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all the acts necessarily need to be performed. Also, those acts that are not dependent on other acts may be performed in parallel with the other acts. The scope of embodiments is by no means limited by these specific examples. Numerous variations, whether explicitly given in the specification or not, such as differences in structure, dimension, and use of material, are possible.
,CLAIMS:1. An antibulging flexitank for transporting liquid, the antibulging flexitank comprising:
a rib reinforcement structure wrapped around the flexitank, wherein the rib reinforcement structure comprises webbing for reinforcement.

2. The antibulging flexitank as claimed in claim 1, wherein the rib reinforcement structure
breaks the wave formed inside antibulging tank due to sloshing of the liquid.

3. The antibulging flexitank as claimed in claim 1, comprising one or more rib reinforcement structure.

4. The antibulging flexitank as claimed in claim 1, wherein the rib reinforcement structure is a tubular woven Polypropylene (PP) fabric wrapped around the inner part of the flexitank.