JP7495453B2 - How to transport liquids using flexitanks - Google Patents

Description

Patent Law Article 30, Paragraph 2 applied Effect confirmation test Date of test: May 6, 2022 Place of test: Kamaishi Mines Co., Ltd.

The present invention relates to a liquid transport method, and more specifically to a transport method using a flexitank.

In Japan, liquids are transported by car or container using one-gallon cans (18 liters) or pails (20 liters are the mainstream) for small amounts, drums for around 200 liters, and IBCs (Intermediate Bulk Containers) for amounts of around 1,000 liters.
For larger volumes, transportation by tanker trucks (trucks and trailers) and tank containers is the norm.

Recently, flexitanks have been attracting attention for transporting beverages, animal and vegetable oils, and other items. Flexitanks began to be used in Europe around 2000 as containers for transporting liquids using international marine containers, and are now commonly used for transporting liquids other than hazardous materials.

In the case of natural water or preserved water, it is filled into PET bottles, packed into cardboard boxes, loaded onto pallets, and transported in rail containers or trucks.
In the case of raw water, the water is transported by placing an inner bag inside a drum (200 liters) or a cubic container called a maxicon (a type of IBC: 1,000 liters). When using a rail container, 23 drums or 4 maxicons can be loaded into one container.

As orders for raw water increased, it became necessary to take measures to improve loading efficiency, cargo handling efficiency, and extraction efficiency.
Transportation by drums has relatively good loading efficiency, but when the quantity to be delivered per shipment is large, there is a problem in that loading and unloading operations, such as filling the drums, loading them into containers, unloading them, and removing the goods from the drums at the delivery destination, are extremely time-consuming.

Although transport by Maxicon allows for a large load capacity, the weight of the containers means that the loading rate is low, and there are also other problems, such as the time required for loading and unloading, which increases the transportation costs.

As described above, in order to build an efficient raw water transportation system, it was necessary to consider various means of transportation from the standpoint of improving the loading rate and the efficiency of loading and unloading operations.
From the standpoint of improving loading rates and loading/unloading efficiency, transportation by tank trucks or tank containers could be considered, but in terms of transportation costs, they are not suitable for transporting raw water, which has little added value.

Therefore, the present inventors focused on transportation using flexitanks.
Flexitanks are large-capacity containers made of flexible materials such as polyethylene, and by placing them inside a container for transportation, the loading efficiency can be improved.

However, when liquid is filled into a flexitank for transport, the liquid is in a fluid state rather than a solid state, and the various forces that arise during transport can cause the flexitank to deform. If the flexitank deforms during transport, it is possible that the container will break due to excessive weight being applied to certain areas.

One way of safely transporting flexitanks is to form a rigid structure on the outside of the flexitank to protect it (Patent Document 1). The technology described in Patent Document 1 is thought to be effective in protecting the flexitank, but it is not expected to significantly improve handling, and the benefits of flexitanks cannot be fully utilized due to factors such as transportation costs.

The inventors discovered that the above problems in transporting liquids using flexitanks can be solved by tying the flexitank with lashing belts to make it nearly solid (primary tying process), and then tying it down in that state by pressing it against the floor of the container (secondary tying process). They previously applied for and obtained a patent (Patent No. 6495425: Patent Document 2).

While the inventors were monitoring the usage of this patented technology in order to further improve it, they discovered a case where drinking water had leaked from a secured flexitank during transport in a rail container, and it became necessary to take measures to prevent leakage.

JP 2013-501685 A Patent No. 6495425

The present invention relates to improvements in a liquid transport system that uses flexitanks secured with lashing belts, and aims to solve the problem of water leakage and provide a stable method for transporting liquids.

During rail container transport, cardboard products can occasionally become "rubbed" and the packaging can become damaged. This is thought to be caused by continuous, long-term micro-vibrations during train transport.

A detailed inspection of the leaking flexitank revealed that the leakage was not caused by friction between the tank's outer bag (polypropylene cloth) and the lashing belt at the fastening position, but rather by damage believed to be caused by friction on the inner surface of the tank's inner bag (polyethylene) at the location corresponding to the fastening position. Furthermore, the damage was concentrated at the top, forward in the direction of travel of the tank. Figure 3 shows the inspection results of the leaking flexitank inner bag, with the damaged area marked with an x.

The present inventors speculate as follows about the damage observed on the inner surface of the tank inner bag.
When the flexitank is secured with lashing belts, the outer bag is concave and the inside of the inner bag is convex, so that both the concave part of the outer bag and the convex part of the inner bag are close to "acute angles" (see Figure 4).
The continuous vibrations during transport by train cause slight shifts in the liquid inside the tank, but once the liquid has moved over the convex part of the inner bag, friction occurs between the inner bag and the liquid.
Although this frictional force may have been minute, as transportation continued for a long period of time, it was thought that the accumulation of this friction may have damaged the inner surface of the inner bag of the tank, and that this damage may have further extended to the outer bag.
They also considered that the damage was concentrated at the upper part of the tank ahead in the direction of travel due to interference between the flow of liquid moving forward in the direction of travel and the flow of liquid moving over the convex part.

Based on this assumption, we tried to make the convex part on the inside of the inner bag gentler or to eliminate the convex part altogether. In other words, when fastening the flexitank with a belt, we placed a cushioning material (a blanket with thick cardboard on top of it) between the belt and the tank, so that the concave part of the outer bag and the convex part of the inner bag caused by fastening were made extremely gentle (see Figure 5).
The lashed flexitank was then placed in a container with measures in place to prevent water leakage and a test was conducted using rail transport. As a result, no water leakage was observed and the transport went smoothly.

The inventor discovered that the above problems could be solved by placing a cushioning material at the fastening position as described above in a method of transporting liquid using a fastening belt in a flexitank, and thus arrived at the present invention.

This invention is a method for transporting liquids using a flexitank, in which the flexitank is fastened in a nearly solid state and fixed to a container in that state, characterized by the inclusion of a cushioning material at the fastening position, and is based on the following technology.

(1) A method for transporting liquids using a flexitank loaded in a container, the method comprising a primary securing step in which multiple lashing belts are wrapped around the flexitank itself in both the vertical and horizontal directions to secure it in a nearly solid state, and a secondary securing step in which the primarily secured flexitank is secured by wrapping lashing belts around it using cargo collapse prevention fittings on the container floor to press it down against the floor,
A method for transporting liquid using a flexitank, characterized in that by placing a cushioning material between the flexitank and the lashing belt, convex protrusions on the inside of the tank caused by the lashing belt digging into the flexitank at the fastening position are suppressed.

(2) A method of transporting liquids using the flexitank described in (1), characterized in that the cushioning material is placed only in the vicinity of the lashing belt at the forward lashing position in the transport direction.

Transporting liquids using the fastening means of the present invention has the advantage of improving loading rates, improving the efficiency of loading and unloading operations, and reducing capital investment in loading and unloading facilities, as well as preventing liquid leakage accidents even during long-distance transport.

FIG. 1 is a photograph showing a flexitank. FIG. 2 is a diagram showing the secured state of the flexitank in Japanese Patent No. 6495425. FIG. 3 is a diagram showing the location of damage to a leaking tank. FIG. 4 is a diagram showing the state in which a lashing belt is directly attached to a flexitank. FIG. 5 is a diagram showing an embodiment of the present invention (a state in which a cushioning material is arranged in a flexitank).

When transporting liquids using flexitanks, the liquid is not in a solid state even after it is filled, but is more like a fluid, so the flexitank is subject to significant deformation due to various forces during transportation. If the flexitank deforms during transportation, it is thought that the risk of the container breaking increases due to the excessive load being applied to certain parts.
Therefore, when transporting liquids using flexitanks, the liquid needs to be in a state closer to a solid in order to be transported safely.

For this reason, as a primary securing measure, the flexitank itself is wrapped around in lashing belts in both the vertical and horizontal directions in advance to make it somewhat solid. At this time, in order to prevent the part of the flexitank that is fastened by the lashing from protruding inwards, cushioning material is placed at the securing position, and the lashing belts are laid with the cushioning material in between.
This makes it possible to prevent convex protrusions on the inside at the fastening position, reducing friction that occurs when the liquid contents move over the convex portion and preventing damage to the inner bag.

As cushioning materials, blankets, thick cardboard, and other packaging materials that allow the lashing belts to bite in more gently and do not damage the outer tank bag can be used, and using them in combination is even more effective.

Next, the flexitank is secured to control its fluidity and become somewhat solid, and then as a secondary securing measure, lashing belts are placed horizontally or diagonally using cargo-shift prevention fittings on the container floor, and secured against the floor to make it even more solid.

One embodiment of the present invention is shown in Fig. 5. The figure shows a state in which a thick blanket (cushioning material 6) is placed on the flexitank 1 as a cushioning material, and then a thick cardboard box (cushioning material 7) is placed on top, and then the tank is fastened with the lashing belts 3.
As a result, there were no liquid leakage accidents and the transportation was completed safely.
In areas where the cushioning material was present, there were fewer internal irregularities and no friction was generated between the flexitank's interior material and the liquid, so no damage occurred.
The positions at which the cushioning material is provided do not necessarily need to cover all of the fastening positions, and it was effective to provide the cushioning material only at the fastening positions forward in the transport direction.

This invention makes it possible to build an efficient transportation system for transporting liquids using flexitanks without causing leakage accidents, and it is possible to improve the loading rate and the efficiency of loading and unloading operations, making it of great practical value.

1 Flexitank
2 Container floor 3 Lashing belt (for lashing tanks)
4 Lashing belts (for cargo collapse prevention fittings)
5. Metal fittings to prevent cargo from shifting 6. 7. Cushioning material

Claims (2)

A method for transporting liquid by mounting a flexitank on a container, comprising the steps of:
The primary securing process involves wrapping the flexitank itself with multiple lashing belts in both the vertical and horizontal directions, securing it in a nearly solid state.
The secondary securing process involves fastening the flexitank to the floor using lashing belts and anti-shift fittings on the container floor to hold it down.
A liquid transport method using a flexitank comprising:
A method for transporting liquid using a flexitank, characterized in that by placing a cushioning material between the flexitank and the lashing belt, convex protrusions on the inside of the tank caused by the lashing belt digging into the flexitank at the fastening position are suppressed. The liquid transport method using the flexitank described in claim 1, characterized in that the cushioning material is placed only near the lashing belt at the forward fastening position in the transport direction.