There are a few ways to transport liquid across nations. Apart from using flexitank containers, there are other methods such as using drums or barrels made out of steel, plastic, or dense paperboard designed to transport 55 gallons of liquid; There are intermediate bulk containers (IBC) capable of transporting up to 1,000 liters. There are ISO tanks that are designed to transport large quantities of liquid. All the options have its merits, and flexitank containers certainly have many advantages of use as compared to its alternatives.
A flexitank, also known as a flexi bag has a common misconception that it is actually – a Tank, flexitank containers are a simple concept to understand. It is a bag designed to fit in a 20’ container.
Fitting a flexi bag or flexitank container into an ISO 20’ container does require some preparation beforehand; it is an industry practice that the equipment and tools required to prepare the container are sold together with the flexitank itself. Here in this article, we will explore everything we need to know about flexitanks, and whether you can take advantage of this logistic tool.
Table of Contents
Materials of Flexitank Containers
A flexitank is commonly made out of durable LDPE or HDPE plastics, or Polyethylene plastic. Flexitanks are also made out of PP plastics (Polypropylene plastics).
These materials are used to make flexitanks because it is: –
- Flexible yet rigid
- UV resistant
- Chemical resistant
- Impact resistant
- Temperature resistant
Flexitanks made out of PP plastics are generally more expensive than Flexitanks made out of PE plastic because PP manufacturing is more complex and also more fatigue resistant.
In modern times, flexitanks are made with at least 2 layers with a combination of PE and PP plastic, in order to amalgamate attributes of both PE and PP plastics into the flexitank.
Design of Flexitank Containers
As we suggested, the primary use of a flexitank is to store liquid into containers. Hence, the flexitank’s design has to fit snuggly into a 20’ container.
If one were to fully inflate a flexitank with air, it will poof up to look like a giant pillow. The reason why it ultimately ends up looking like a pillow is because manufacturers wants it to fit a container, which is rectangle, and yet requires the least seams to manufacture the flexitank.
Flexitank Container Valves
A Flexitank containers has 2 or more valves installed, there are three variants of valve installations: –
- Top Loading/Bottom Discharging (TL/BD)
- Bottom Loading/Bottom Discharging (BL/BD)
- Top Loading/Top Discharging (TL/TD)
To decide which variants to choose to transport liquid depends on the viscosity, density and temperature of the liquid cargo.
Different viscosity, density or temperature of the liquid will react very differently to the external forces during cargo transit.
Above all else, a cargo owner should be well aware of the properties of their transported liquid and therefore are able to decide which variant of valve location to choose from.
More importantly, the valves installed are designed for one-way traffic only, hence the use of 2 or more valves; One for liquid inflow, and one for liquid outflow.
Flexitank valves are either made from plastic heat-sealed fittings, or stainless-steel bolted fittings. Once again, the liquid cargo attributes such as temperature, viscosity, and density decide which valve material to use.
Frequently Asked Questions about Flexitank Container
How much does it cost?
Flexitanks are very cost efficient. The easy answer is: it depends on what type of flexi bag purchased.
The price of a flexitank container set ranges from 100 USD/set up to 500 USD/set. The most generic type used in a standard 20’ container, that comes with plastic heat-tested valves are around 150-200 USD per set.
The flexitanks are mostly manufactured in china, and it comes with: –
- Door baffle/Bulk head
- Corrugated Papers
- Steel bars
- Adhesive tapes
- Caution tags
How to Install a Flexitank Container?
Step 1: Ensure that the 20’ container is fully prepped and ready to be installed with Flexitanks
Container selection is key, an exporter must always choose a food-grade, “seaworthy” container.
Additional Reading: Is my container seaworthy?
A food-grade, “seaworthy” container essentially does not have rusts, oil stains, or holes in the container.
Step 2: Clean the container
After requested for a seaworthy container, installers also should do further checks to make sure the container’s door are able to close properly, and free from dents. The installers should also clean the container thoroughly to eliminate nails, glasses, or any sharp wastes from previous cargo use.
Step 3: Line the container wall with Corrugated paper
A flexitank container set comes with corrugated papers, installers will have to tape the corrugated papers on all four sides of the wall and also the container floor.
Step 4: Place the folded flexitank into the center of the container
Step 5: Unfold and install flexitank in the container
When you start to unfold the flexitank in the container there are a few things to look out for: –
- Make sure the delivery hose is place on the right-hand side of the container’s 2 doors.
- Make sure there is sufficient room to install the bulkhead and valves
- Secure the flexitanks onto the hooks of the container
Step 6: Install Bulkheads
Make sure there is enough room to close the container door once the bulkhead and valves are installed.
Step 7: Install flexitank valves
Step 8: double check the container door closing
Close the left-hand side container door to make sure once again that the container is able to close shut after installing the bulkhead.
Step 9: Paste the adhesive warning label on the top right-hand side of the container door
What is a flexitank’s capacity?
A standard 20’ container flexitank has the capacity to load up to 24 MT of liquid cargo
What can be loaded onto a flexitank?
Here is a list of liquid cargos that are commonly transported using a flexitank. Note that a flexitank container cannot load hazardous liquids.
| Foodstuffs | Wine Edible oil Fruit Juices Additives Palm oil or Coconut Oil Sauces and Syrups |
| Industrial Oils | Oil lubricants Oil additives White oil Tung oil Fatty acids Engine/Hydraulic oils |
| Non-Hazardous Liquid Chemicals | Resins Plasticizer Detergent Disinfectants Fertilizers Latex Saline/Salt solutions Alkylating agents Polyether |
