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This section is used to easily answer the most frequently asked questions from our customers.

The Flexitank, also called flexi-tank, flexibag or flexible tank, is a large flexible bag or tank that transforms a conventional 20'DV shipping container into a bulk liquid shipping tank.

In a Flexitank can be transported between 16,000 and 24,000 liters. Our Flexitanks are made to match the product being transported, adapting to its density and the maximum net payload for that container and trip. The model will depend on the product transported, the weight limitations established by the shipping line as well as the road traffic limitations of the roads/rail network connecting the port in the receiving country.

Some examples of the most common flexitanks according to the type of product:

Product Volume in litres
Wine 24000 l
Olive Oil 24000 l
Palm oil 24000 l
Glycerin 19000 l

In general, almost all types of non-hazardous liquids can be transported.

Our Flexitanks are single-use. This ensures that the transported product always travels in the best conditions, avoiding contamination from previous trips. It also minimises the risk of equipment failure once it has been used.

According to the physical characteristics of the product, atmospheric conditions of the transit routes as well as the range of optimum conservation temperatures, we have isothermal systems which are installed inside the sea container together with the flexitank.

These systems provide an optimal thermal range for the product durin its transit time and stays until it is discharged at destination.

See our section on thermal services for more information or contact our sales department.

The solidification of goods when they cool down during transit often causes problems when unloading the product at destination.

To solve these problems we have systems specially designed to heat the cargo at destination. These are heating pads which, when installed, allow the product to be heated until it is liquefied, thus making it possible to unload it.

See our section on thermal services for more information or contact our sales department.

Depending on the number of layers with which a flexitank is manufactured we can identify 2 groups:

  • Multilayer Flexitanks: These flexitanks are composed of several bags (layers) of polyethylene, where each bag is housed and encapsulated in another bag superior. These layers are thin and flexible, allowing better handling at more competitive costs. The usual in these models is to have 3 layers, all and there are models of 2 and 4 layers, depending on the logistic needs and nature of the product.
  • Single-layer Flexitanks: These flexitanks are composed of a single bag (layer). This polyethylene layer is thicker than the ones in the multi-layer ones, giving a more rigid and robust but less flexible format. Despite the fact that they have a slightly higher cost than the multilayer ones, their main advantage is the ease of unloading high viscosity and /or density goods, avoiding losses.

Although the nature of the product may condition the unloading time, the unloading of a flexitank is a simple process.

Once the flexitank is received at destination, just open the right door, connect the discharge pump with its hose to the 3-inch camlock-type valve, open the valve and start the start the unloading process. The process can take between 30 and 60 minutes, depending on both the pump performance and the density and viscosity of the product.

When there is not much remaining, and to avoid any loss, the best thing to do is to bend the flexitank as if it were a tube of toothpaste. In this way, the remaining product is directed towards the valve of the flexitank and is discharged almost completely.

The flexitank, once unloaded, has to be dismantled to return the container completely empty to the sea terminal allowing the shipping line to re-use it again for other trip. This service, as well as its recycling under environmental regulations, we can optionally offer this service to our customers in the most important Spanish ports. Do not hesitate to contact our commercial agents for more information.

Here are some important recommendations when working with pumps that interact with flexitank equipment:

  • Highly recommended, self-priming and positive priming pump.
  • Rotary pumps (for wine or food oils), diaphragm or helical pumps for high density and/or high viscosity products are recommended.
  • The pump can be 2, 3 or 4 inches, with a flow rate of 756 liters per minute (0.01 m3/s) or more.
  • To assess the required capacity and range of the pump it will be essential to consider:
    • The length/height and product to be pumped ('head')
    • The length and suction lift required from the pump/tank to the Flexitank
    • Solid contents in the product
    • Diameter and condition of the pipes of the installation.
  • In the case of pumping food product, all equipment and piping must be validated for such use.
  • The filling flow for the pump should be adjusted to 200L per minute until the first 3000L are already filled and the Flexitank has been correctly deployed. Once there, the flow rate can be increased to 800L per minute.
  • Make sure the Flexitank is not filled with air (Max 50L).

Bulging is the lateral deformation of the container walls caused by the pressure of the Flexitank once it is full. Unfortunately this is a fact that occurs more and more often as container manufacturers save costs by producing units with thinner walls. This practice was not so common 10 years ago.

Flexitank España offers additional services with lateral container reinforcement systems to counteract these deformations.

Get your cargo on board ever in time.

Please do not hesitate to contact our commercial agents for further information.

The tolerance is the safety interval that defines the upper and/or lower limits within the performance of the Flexitank equipment is stable and reliable. Flexitanks work with tolerances, that is the maximum and minimum filling volumes with which the bag can travel safely.

Normally this tolerance is +- 500 litres. For example, a 24,000 litre Flexitank can be loaded with a maximum of 24,500 litres and a minimum of 23,500 litres.

It is very important to respect these parameters in order to keep the Flexitank running stably and reliably, for the safety of transport.

Not complying with the established filling tolerances can generate instability and internal waves, in the case of filling below the tolerance, and an overstressing of the bag as well as bulging in the container, in the case of exceeding the upper limit of the tolerance with an overload.

Do not hesitate to contact our technical department for further information.

Yes, in fact it's one of our most powerful lines of business. We work with the main companies in the sector offering B2B services, especially adapted to freight forwarders and shipping lines, offering the possibility of outsourcing this complex service in the hands of fully specialized professionals.

Please, see our section for specialized services or more information taking contact with our sales department.

The maximum temperature is 60ºC and the minimum temperature is 0ºC

This factor is important as outside this temperature range the PE polymers in the bag films can be degraded and the seals can be affected with the risk involved.

It is very important to respect these parameters in order to keep the Flexitank performance stable and reliable, for the safety of transport.

If you need to load product with temperature higher than 60ºC or lower than 0º please consult our technical department to study special manufacturing options.

Please, see our section for specialized services or more information taking contact with our sales department.