Various types of containers are in use today which helps in quick and efficient handling of the cargo. Flexitank is the latest type of container which is basically a flexible bag and is usually placed inside a dry freight container and is then filled with liquid cargo. Shipment of liquids in flexitanks is becoming a usual substitute to drums and tank containers as well as canisters.
Flexitanks are made using rubber, nylon, polyethylene or plastic, a flexible “inflatable” bag type, which is placed within a traditional 20-foot dry freight container, prior to being filled with the liquid cargo via a valve opening either at the bottom end or on top.
Various types of flexitanks are available in the market such as:
- Affordable single layer bags made of polypropylene or plastic. These may be very susceptible to cuts, which can result in the complete or partial loss of the cargo.
- More costly multi-layer bags include five to six-ply polyethylene and a polyethylene fiber woven outer layer. These are stronger and more defiant to damage than single layer bags.
- Rubber bags
Understanding the procedure for loading and discharging
In order to load the flexitank, the liquid is pumped in after connecting the hose to the loading connection. It takes about half an hour to fill up the flexitank however, it depends on the type of cargo, and after completion the container and flexitank are all set for transportation by rail, sea or road. At the place of delivery, the only equipment which is needed is a pump to set free the cargo. Certain liquids showcase certain physical and chemical properties whereby they become more viscous during storage or lower temperatures. To enable the smooth unloading of such cargoes, a heating pad is installed in the container, along with the flexitank. As per the manufacturers of flexitanks it is possible to transfer almost any non-perilous liquid in this way, whether for industrial, chemical or food application. But it is important to note that flexitanks are not right for the carriage of hazardous cargoes.
Recommendations before installing the flexitank
As the flexitank is becoming more and more popular, certain precautions are essential to limit the risk of leaking flexitanks. Prior to the flexitank is placed in the container, the below mentioned points should to be carried out:
- Get rid of any protruding screw or nail in the floor plating and any other sharp or protruding part
- Carefully inspect the inside of the dry freight container for any defect or damage.
- Ensure that the lower part of the container is lined with cardboard lining and is fixed properly to the container sides and floor.
- Cover the sharp edges and welding seams with tape.
- Use wooden bracing at the door, with a gap in the lower part for the valve of the flexitank
- Make sure that there is enough space between the container doors and the filling valve when they are closed.
- Install over-pressure valves if the cargo may start fermentation
Following these recommendations prior to the installation of flexitanks would enable the users to make the best use of it.