Flexitank for liquid transportation

Abstract

A flexitank for liquid transportation, comprising an inner bladder, an outer bladder, a loading-unloading port and waistbands. The inner bladder comprises an outer layer and an inner layer; the outer layer is made of a PP material, and has a gram weight of 140-240 gsm and a weave density of 12*12-17*17 threads / inch; the inner layer is made of a PE material, and has a film thickness of 50-300 um; the loading-unloading port is a valve, the valve being made of a PP material; the waistbands are high-strength polyester woven belts, the number of which is 4-10. A flexitank body has higher overall strength, can withstand in transportation processes the impact of liquid sloshing on the flexitank body without leakage and, after being filled, can satisfy transportation requirements without the need for the support of four side walls of a container.

Description

A flexible liquid bag for liquid transportation Technical Field

[0001] The patent of this invention relates to a liquid bag for container and train transportation, belonging to the field of packaging materials for transportation. Background Art

[0002] Liquid bags, a method for long-distance transport of liquid commodities that first emerged in the 1980s, are primarily used to transport non-hazardous liquids and related chemicals. This technology has seen widespread adoption and significant growth in global logistics and transportation in recent years, primarily due to advances in materials and manufacturing technology for large, flexible liquid bags, as well as the development of containerized transportation. Compared to canned transport, liquid bags offer advantages such as no empty runs, no need for cleaning, low costs, and easy loading and unloading. They are widely used in the food, petroleum, and chemical industries.

[0003] With the increasing prevalence of containerized liquid bags in liquid packaging and transportation, the environments in which they are used are becoming increasingly diverse. With the widespread adoption of containerized liquid bag packaging and transportation in international container transport, this technology has also penetrated into inland onward transportation, especially international rail transport. Winter temperatures in Russia are extremely low, with outdoor temperatures dropping below -40°C. Russia also spans a vast east-west region, stretching from the western region to the eastern coast. Bulk cargo must be transported by rail, over distances of over 5,000 kilometers. When transporting liquid bags by rail, the train generates high-frequency vibrations, causing the bag to vibrate along with the train. The PE film used in liquid bags gradually hardens and loses its flexibility as the temperature drops. Under these high-frequency vibrations, the edges and corners of the bag are prone to developing pinhole-like holes, leading to cargo leakage.

[0004] The materials used in container flexitanks have evolved from cloth-and-rubber to polyurethane, polyvinyl chloride, and polyethylene composites. Currently, to meet increasingly stringent environmental regulations, container flexitanks are primarily made of environmentally friendly polyethylene and are primarily disposable. These flexitanks are available in either multi-layer or single-layer configurations. Multi-layer structures typically utilize four layers of polyethylene for the inner layer and a woven polypropylene outer layer; single-layer structures utilize polyethylene. Current flexitank configurations can develop small holes in corners during transportation, leading to cargo leakage, environmental pollution, and a significant increase in accident handling costs.

[0005] When transporting liquid cargo in larger containers like 40-foot and 53-foot containers or European-style trucks, existing structural flexitanks are too long, causing the liquid to slosh back and forth a greater distance inside the container, resulting in greater impact forces on the ends of the flexitank. The ends of existing structural flexitanks are reinforced by sewing or heat-sealing, but these ends are not strong enough to meet operational requirements, leading to bursting and leaks.

[0006] Factors such as production process, product size, valve safety, vehicle condition, and type of liquid loaded can all affect the safety of liquids, leading to leakage and, in severe cases, tearing of liquid bags during transportation. Therefore, strengthening and improving these key areas is a must-solve issue in the development of liquid bag transportation.

[0007] CN102756523A discloses a flexible liquid packaging bag film for containers. The film is produced using a small three-layer co-extrusion unit using a blend of olefin-based specialty elastomers, mLLDPE, and DLPE. The film exhibits enhanced tensile strength, puncture resistance, ductility, flexural strength, and bending resistance, improving the safety of liquid bags. It is less likely to rupture at low temperatures and reduces transportation costs.

[0008] Summary of the Invention

[0009] The present invention discloses a flexible liquid bag for liquid transportation, comprising an inner bag, an outer bag, a loading and unloading port, and a waist belt; the inner bag comprises an outer layer and an inner layer; the outer layer is made of PP material with a gram weight of 140-240gsm and a weaving density of 12*12-17*17 strands / inch; the inner layer is made of PE material with a film thickness of 50-300um; the loading and unloading port is a valve made of PP material; the waist belt is a high-strength polyester braided belt, and the number of the belts is 4-10.

[0010] Preferably, the outer layer is a PP film barrel material with a gram weight of 160-220 gsm, more preferably 165-180 gsm, and a weaving density of 14*14-15*15 strands / inch.

[0011] Preferably, the inner layer is a PE film barrel material with a film thickness of 100-200 μm, more preferably 120-150 μm; the thickness and number of layers of the PE film barrel material can be selected according to the properties of the filled goods, and the number of layers of the PE film barrel material is 1-10 layers, more preferably 2-5 layers, and most preferably 3-4 layers; the PE film is in direct contact with the liquid, playing a role in sealing and ensuring the quality of the goods.

[0012] Preferably, the loading and unloading port is a 2-5 inch PP valve, more preferably a 3-4 inch PP valve.

[0013] Preferably, the inner PE film barrel material is sealed by melting welding;

[0014] Preferably, the outer PP film barrel material and the inner PE film barrel material are connected together by sewing, so that the inner and outer layers form a whole.

[0015] The outer bag is made of PVC or TPU mesh cloth sheet with a gram weight of 550-1000gsm, preferably 600-650gsm, and a mesh cloth weaving density of 12*12-23*23 threads / inch, preferably 14*14 threads / inch.

[0016] The outer bag provides the inner bag with sufficiently high strength to prevent the bag from bursting due to impact during transportation. At the same time, the outer bag material itself also has a sealing effect, providing a secondary sealing effect for the bag body.

[0017] The outer bag is welded by hot air welding or high frequency welding to heat the sheet material into a tube material. The heat-sealed joint adopts an overlap method and its width is 3-8cm, more preferably 4-6cm. This heat-sealed joint is located in the middle of the bottom of the bag body and is pressed by the bag body after filling, which reduces the strength requirement of the weld.

[0018] After placing the inner bag as a whole on the outer bag tube, weld both sides of the tube tightly. Heat seal the joints by overlapping or flat heat sealing followed by folding and secondary heat sealing.

[0019] Preferably, the outer portion near the end of the bag is provided with a cross-shaped valve opening after the surface is reinforced with multiple layers of PVC mesh, and a throat clamp is used to fix the valve to the outer bag.

[0020] The belt is a high-strength polyester woven belt with a width of 5-6 cm and a tensile strength of ≥3000 kg; 2-4 belts are preferably used, and the number used is determined according to the specific gravity and viscosity of the transported goods; it is used to control the volume of the bag and reduce the amplitude of liquid shaking during transportation.

[0021] The length of the inner bag is 1m longer than the length of the outer bag tube, and more preferably 1.5m longer, so as to reduce the stress on the inner bag after filling and during transportation.

[0022] Preferably, an anti-skid mat is placed on the contact surface between the floor and the liquid bag to increase the friction between the bag and the floor; the anti-skid mat is a recycled sponge or rubber sheet with a thickness of more than 1 cm, which provides support strength for the inner layer and protects the inner bag from wear.

[0023] Functions of protective pads: 1) prevent damage to the bag caused by wear and tear on the floor; 2) reduce the forward and backward displacement of the liquid bag during transportation.

[0024] The stated weight is for a cutting area of ​​50mm 2 The sample is converted into weight after testing, and the weight of the sample is calculated.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The bag body is stronger and can withstand the impact of liquid shaking on the bag body during transportation without leakage; after filling, it can meet transportation requirements without relying on the support of the side walls of the container. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG1 is an overall schematic diagram of the flexible liquid bag;

[0028] Figure 2 Schematic diagram of thermal synthesis of outer bag sheet material;

[0029] Figure 3 is a schematic diagram of the inner bag being sealed by overlapping welding;

[0030] Figure 4 is a schematic diagram of the inner bag being sealed by flat welding;

[0031] Figure 5 is a schematic diagram of the inner bag being folded and heat-sealed for the second time after heat-sealing. DETAILED DESCRIPTION

[0032] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

[0033] Example 1

[0034] A flexible liquid bag for liquid transportation, comprising an inner bag, an outer bag, a loading and unloading port, and a waistband; the inner bag comprises an outer layer and an inner layer; the outer barrel material wrapping layer is made of PP material with a gram weight of 180gsm and a weaving density of 16*16 strands / inch; the inner layer is made of PE material with a film thickness of 120um; the loading and unloading port is a 3-inch PP material valve; the waistband is a high-strength polyester braided belt with a width of 5cm, and the number of belts is 4; the outer bag is made of sheet material heat-sealed into barrel material by high-frequency welding, and the heat-sealed joint adopts an overlapped method with a width of 4cm; this heat-sealed The joint is located in the middle of the bottom of the bag body and is compressed by the bag body after filling, which reduces the strength requirements of the weld; after the inner bag is placed as a whole on the outer bag tube, the two sides of the tube are welded tightly, and the heat-sealed joint is heat-sealed by overlapping and then folded for a second heat-sealing connection; the length of the inner bag is 1m longer than the length of the outer bag tube to reduce the stress on the inner bag after filling and during transportation; a non-slip mat is placed on the contact surface between the floor and the liquid bag to increase the friction between the bag and the floor; the non-slip mat is a recycled sponge or rubber sheet with a thickness of 1cm, which provides support strength for the inner layer and protects the inner bag from wear.

[0035] Example 2

[0036] A flexible liquid bag for liquid transportation, comprising an inner bag, an outer bag, a loading and unloading port, and a belt; the inner bag comprises an outer layer and an inner layer; the outer barrel material wrapping layer is made of PP material with a gram weight of 180gsm and a weaving density of 16*16 strands / inch; the inner layer is made of PE material with a film thickness of 150um; the loading and unloading port is a 3-inch PP material valve; the belt is a high-strength polyester braided belt with a width of 6cm, and there are three of them; the outer bag is made of sheet material heat-sealed into barrel material by hot air welding, and the heat-sealed joint adopts a flat joint method with a width of 4 cm; this heat-sealed joint is located in the middle of the bottom of the bag body and is compressed by the bag body after filling, reducing the strength requirements of the weld; after the inner bag is placed as a whole on the outer bag tube, the two sides of the tube are welded tightly, and the heat-sealed joint is connected by overlapping heat sealing; the length of the inner bag is 1.5m longer than the length of the outer bag tube to reduce the stress on the inner bag after filling and during transportation; an anti-slip mat is placed on the contact surface between the floor and the liquid bag to increase the friction between the bag body and the floor; the anti-slip mat is a 2cm thick rubber plate that provides support strength for the inner layer and protects the inner bag from wear.

[0037] Example 3

[0038] A flexible liquid bag for liquid transportation, comprising an inner bag, an outer bag, a loading and unloading port, and a belt; the inner bag comprises an outer layer and an inner layer; the outer barrel material wrapping layer is made of PP material with a gram weight of 200gsm and a weaving density of 14*14 strands / inch; the inner layer is made of PE material with a film thickness of 120um; the loading and unloading port is a 3-inch PP material valve; the belt is a high-strength polyester braided belt with a width of 5cm, and there are two of them; the outer bag is made of sheet material heat-sealed into barrel material by high-frequency welding, and the heat-sealed joint adopts an overlap method and is 6cm wide; The heat-sealed joint is located in the middle of the bottom of the bag body and is compressed by the bag body after filling, reducing the strength requirements for the weld; after the inner bag is placed as a whole on the outer bag tube, the two sides of the tube are welded tightly, and the heat-sealed joint is heat-sealed by overlapping and then folded for a second heat-sealing connection; the length of the inner bag is 1m longer than the length of the outer bag tube to reduce the stress on the inner bag after filling and during transportation; a non-slip mat is placed on the contact surface between the floor and the liquid bag to increase the friction between the bag and the floor; the non-slip mat is a recycled sponge with a thickness of 2cm, which provides support strength for the inner layer and protects the inner bag from wear.

[0039] The resulting products were subjected to performance testing. Mechanical performance testing was conducted according to ASTM D751. Tear strength testing was performed at a clamping speed of 5±0.2 mm / s, a clamp spacing of 75 mm, and a sample size of 25 x 152 mm. Tensile strength testing was performed at a clamping speed of 5±0.2 mm / s, a clamp spacing of 75 mm, and a sample size of 25 x 152 mm. Heat seal tensile testing was performed at the following parameters: temperature 500°C, air flow 80%, heat seal speed 2.5 m / min, sample width 15 mm, and tensile speed 100 mm / s. The test results are shown below.

[0040] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A flexible liquid bag for liquid transportation, comprising an inner bag, an outer bag, a loading and unloading port, and a waistband; the inner bag comprises an outer layer and an inner layer; the outer layer is made of PP material, with a gram weight of 140-240gsm and a weaving density of 12*12-17*17 strands / inch; the inner layer is made of PE material, with a film thickness of 50-300um; the loading and unloading port is a valve, and the valve is made of PP material; the waistband is a high-strength polyester braided belt, and the number of the belts is 4-10 strands.

2. The flexible liquid bag according to claim 1, characterized in that The outer layer is a PP film barrel material with a gram weight of 160-220gsm, more preferably 165-180gsm, and a weaving density of 14*14-15*15 strands / inch.

3. The flexible liquid bag according to claim 1, characterized in that The inner layer is a PE film barrel material with a film thickness of 100-200um, more preferably 120-150μm; the PE film barrel material can select an appropriate thickness and number of layers according to the properties of the filled goods, and the number of layers of the PE film barrel material is 1-10 layers, more preferably 2-5 layers, and most preferably 3-4 layers; the PE film is in direct contact with the liquid, playing a role in sealing and ensuring the quality of the goods.

4. The flexible liquid bag according to claim 1, characterized in that the loading and unloading port is selected to be a 2-5 inch PP valve, more preferably a 3-4 inch PP valve.

5. The flexible liquid bag according to claim 1, characterized in that The inner PE film barrel material is sealed by melting welding; 6. The flexible liquid bag according to claim 1, characterized in that The outer PP film barrel material and the inner PE film barrel material are connected together by sewing to form an integral whole.

7. The flexible liquid bag according to claim 1, characterized in that The outer bag is made of PVC or TPU mesh cloth sheet material with a gram weight of 550-1000gsm, preferably 600-650gsm, and a mesh cloth weaving density of 12*12-23*23 strands / inch, preferably 14*14 strands / inch.

8. The flexible liquid bag according to claim 1, characterized in that The outer bag is welded by hot air welding or high frequency welding to heat the sheet material into a tube material. The heat-sealed joint is overlapped and has a width of 3-8 cm, more preferably 4-6 cm. The heat-sealed joint is located in the middle of the bottom of the bag and is pressed by the bag after filling, reducing the strength requirement for the weld.

9. The flexible liquid bag according to claim 1, characterized in that After placing the inner bag as a whole on the outer bag tube, weld both sides of the tube tightly, and use overlap heat sealing or flat heat sealing followed by folding and secondary heat sealing.

10. The flexible liquid bag according to claim 1, characterized in that Near the end of the bag, the surface is reinforced with multiple layers of PVC mesh cloth to form a cross-shaped valve opening, and a throat clamp is used to fix the valve to the outer bag; The waistband is a high-strength polyester braided belt with a width of 5-6 cm and a tensile strength of ≥3000 kg; preferably, 2-4 waistbands are used, and the number of belts used is determined according to the specific gravity and viscosity of the transported goods; it is used to control the volume of the bag and reduce the amplitude of liquid shaking during transportation; The inner bag is 1m longer than the outer bag tube, preferably 1.5m longer, to reduce the damage to the inner bag after filling and during transportation. force.

Images