Flexible containers

There are three main types of packaging for transporting and storing granulated, powdered or pasty products:

• Bulk, a natural solution for end-use applications requiring very large volumes, when the nature of the products permits;

• The 25 kg bag, intended more particularly for end-use applications requiring small individual quantities, or otherwise not highly mechanized;

• the flexible container, a large-capacity bag characterized by volumes of between 250 and 3,000 L, and nominal loads of 2,000 kg or less.

Compared to the 25 kg bag, the flexible container offers the following advantages, making it the ideal packaging for a multitude of applications:

• reduced handling by users, resulting in higher productivity and better working conditions;

• potential for savings along the supply chain, provided the system is used optimally;

• reduced packaging waste.

On the other hand, the use of flexible containers obviously requires mechanized lifting and handling equipment.

The main users are the chemical industry in general, including the fertilizer industry, the pharmaceutical industry, the food industry, the mining industry and the building materials industry.

The most common models are designed to be lifted by means of one or more handles attached to or formed on their upper part. Schematically, these packages have a dual function: to withstand the stresses of lifting and handling (mechanical function) and to protect the contents (barrier function). These two functions can be performed either by a single envelope, or by superimposing envelopes with complementary properties. The envelope subjected to the main mechanical stresses (working envelope) is most often made from technical textiles assembled by sewing.

The sizing of flexible containers is based on three main criteria:

• optimized loading: the usual means of transport are truck or SNCF wagon trays, on which the bags are arranged vertically in a single layer, and ISO containers, in which several layers can be stacked to make the most of the available height. Loading efficiency is therefore determined by the diameter of the flexible containers, which must be adjusted to the dimensions of the above means of transport;

• standard pallet dimensions in some cases ;

• strength and stability: some standards require a ratio of useful height to diameter of between 1/2 and 2. To be representative of the...